2025 Speakers

Amanda Wiltzius

Inadvertently Captured Evidence in Images and Videos

Mandy Wiltzius has a Bachelor of Science degree in Forensic Science from the University of Central Florida. She was a crime scene investigator with the Charlotte Mecklenburg Police Department for 2 years before becoming a Latent Print Examiner with the Charlotte Mecklenburg Police Department Crime Laboratory in 2008. She joined with Wisconsin State Crime Laboratory in 2014 and is currently holds the Advanced analyst position at the Milwaukee laboratory. She has been IAI certified latent print examiner since 2011. During her time in Milwaukee, she has completed 2 new method validations and 1 method modification validation. She has presented at the International Association for Identification international conference. She is an ANAB technical assessor and assists in writing policies for the latent print unit.

Andrew Nowlan

State and Federal Firearms Eligibility Laws

Andrew joined the Crime Information Bureau in 2015 and currently serves as a Deputy Director
for the Bureau. In this role Andrew is involved with overseeing the day-to-day operations of the
Bureau with special responsibility over the Firearms Section and its programs including the
Handgun Hotline and Carry Concealed Weapon program. Andrew is the Wisconsin Point of
Contact for the National Instant Criminal Background Check (NICS) Section of the FBI and
regularly conducts training around the State of Wisconsin on the Wisconsin and federal
firearms eligibility laws. He is also a member of the NICS Subcommittee of the FBI’s Advisory
Policy Board. Andrew previously served as the Supervisor of the Firearms Section within the
Crime Information Bureau. Prior to working in the Firearms Section, Andrew was the supervisor
of the Justice Programs Section for the Department of Justice, Training and Standards Bureau
after working for 19 years in the Wisconsin Legislature. Andrew has completed the Leadership
in Police Organizations program from the International Association of Chiefs of Police and the
FBI NICS Section’s Train the Trainer program for federal firearms eligibility laws training.
Andrew has a bachelor’s degree in Political Science from the University of Wisconsin-Madison.

Brandi Valeri

Documentation of Ballistic Evidence at Crime Scenes

Documentation of Bloodstains at a Crime Scene

Brandie Valeri is a Certified Senior Crime Scene Analyst and law enforcement professional with over 17 years of law enforcement experience in advanced criminal and forensic investigations in both sworn and civilian roles. She currently serves as a Police Officer with the Mount Pleasant Police Department.

Beyond her role in law enforcement, Brandie is also an entrepreneur and educator. As the owner of Forensic Junkie LLC, she provides law enforcement and forensic-themed merchandise, collaborates with agencies for customized training, and provides forensic consultations. Additionally, she is an Adjunct Instructor at Gateway Technical College, where she teaches numerous topics in the law enforcement recruit academy and has developed and instructed numerous specialized training programs relating to forensics and crime scene investigations.

In addition to her practical experience, Brandie holds dual Bachelor of Science degrees in Criminal Justice and Criminology, and Political Science with a concentration in Law Studies, a certificate in Death Investigation as well as an Associate’s degree in IT Networking Cybersecurity. Her commitment to professional development is reflected in over 600 hours of specialized training in areas such as bloodstain pattern analysis, shooting reconstruction, photography, and courtroom testimony

Brooke Brodzeller

Alternative Light Source Photography

Brooke Brodzeller is a Forensic Imaging Specialist at the Wisconsin State Crime Laboratory in Madison. She has a BFA with a concentration in Photography from Northern Michigan University. Brooke began her career as an Imaging Specialist just over nine years ago where she wears many hats; photographing evidence, creating demonstrative exhibits, providing training to agencies throughout Wisconsin and analyzing video, just to name a few. She has been a member of the International Association of Identification since 2017. As technology advances, Brooke looks forward to learning about imaging processes and how the laboratories can use these technologies in the future.

Charlie Vosters

Kaukauna Double Child Homicide

Sergeant Charlie Vosters has been in law enforcement for 24 years. He received his
Associate’s Degree in Criminal Justice at Fox Valley Technical College in December of
2000. He began his career in law enforcement as a part-time Officer with the Combined
Locks and the Seymour Police Department. He held a full-time police officer position at
the Shawano Police Department from 2003-2005 until choosing to move back to his
hometown of Kaukauna. He has been with the Kaukauna Police Department since
2005. For most of those years he has been, and still is, an evidence technician and
evidence custodian. In 2024 he was promoted to a night shift patrol supervisor and
serves as a Team Leader with the Outagamie County Emergency Response Team.

Erik Schneider

The Halderson Double-Homicide Investigation

Erik Schneider is a Deputy Sheriff with the Dane County Sheriff’s Office where he has been employed for the last 14 years. For the past 10 years, Erik has been a member of the crime scene unit, with the last two years being assigned full-time.

George Mayerhofer

The Halderson Double-Homicide Landfill Search

George Mayerhofer is a Detective with the Dane County Sheriff’s Office where he has been employed for the past 25 years and has been a Detective since 2011.

Jeff Gross

EV Response & Evidence Safety

Jeff Gross began his law enforcement journey as a Madison Police Explorer and Madison Police
Intern before his 31 year full time career with the Appleton, Manawa, and UW-Green Bay Police
Departments as a Police Officer, Sergeant, Lieutenant, and interim Chief. He served as a patrol
officer, neighborhood officer, evidence technician, property room custodian, and investigator
and enjoyed leading by example and as a "working officer" regardless of his leadership level.

As an early adopter of hybrid/electric vehicles he has 16 years ownership and 700,000 miles
driven. After retiring from full-time law enforcement in 2020, he continues to serve first
responders by creating and delivering an electric vehicle safety awareness course to over 6000
first responders in Wisconsin, Illinois, and Michigan. The past 2 years he has delivered electric
vehicle safety, buying and Tesla ownership seminars to over 250 attendees at the Midwest
Renewable Energy Fair. As a side hustle, Jeff continues to drive electric about 30000 miles
annually as an Amazon flex driver in Northeast Wisconsin anytime between 0315-2230 hours.

He has earned a Bachelor's Degree in Social Welfare from UW-Madison, Master's in
Organizational Leadership from Marian College, is a Wisconsin Certified Public Manager,
completed Supervision of Police Personnel from Northwestern Center for Public Safety,
Command Institute for LE Executives from FBI-Leeda, and specialized courses from Federal
Emergency Management and National Fire Protection Association.

Jeff Gurvis

Swipes, Wipes, and Transfer Stains

For more than 29 years, he has been entrenched in the forensic and law enforcement community by providing forensic analyses in the fields of latent print comparisons and bloodstain pattern analysis. He has also served as a project manager for over a decade with the leading laboratory information management systems company, Porter Lee, implementing the BEAST in scores of forensic laboratories and police departments across the US and tailoring the product for each lab’s specific needs.

A recognized veteran in the forensic community, Jeff has played a variety of roles and has garnered recognition within the law enforcement community including being a founding member of Scientific Working Group on Bloodstain Pattern Analysis (SWGSTAIN). He currently serves as the Vice Chair of the OSAC Forensic Science Standard’s Board (FSSB) and Chair of the AAFS ASB Bloodstain Pattern Consensus Body. Jeff also serves on the Board of Directors at the International Association for Identification (IAI) and Vice President of Region 3 of the International Association of Bloodstain Pattern Analysts (IABPA). In addition, Jeff has an extensive forensic background, having trained hundreds of forensic scientists, crime scene personnel, and criminal investigators. He taught for the FBI for over six years and at the University of Tennessee National Forensic Academy for over 10 years. Other organizations where Jeff has been an instructor include the Illinois State Police, Baltimore Police Department, IAI, and the International Association of Bloodstain Pattern Analysts. Jeff’s career began at the Northern Illinois Police Crime Laboratory where he served as a Latent Print Examiner, Crime Scene Response Coordinator, and Bloodstain Pattern Analyst. He is still actively performing forensic examinations as a consultant in the areas of crime scene, latent, and bloodstain evidence for law enforcement departments across the nation. He also is the Co-Founder of Visionations, the makers of CrimePad, a mobile platform for crime scene documentation and management.

Jeff has a BS degree in both Forensic Science and Criminal Justice from Michigan State University as well as an MBA from DePaul University.

Jim Plenty

The Halderson Double-Homicide Investigation

Jim Plenty is a Deputy Sheriff with the Dane County Sheriff’s Office where he has been employed for the last 19 years. For the past 12 years, Jim has been a member of the crime scene unit, with the last four years being assigned full-time. Jim has a total of 30 years law enforcement experience.

Joe LeFevre

Grand Chute Police Department - Case Study – Kidnapping & Sexual Assault

Dr. Joe LeFevre is a full time instructor at FVTC and Deputy Coroner with Outagamie County. Prior to teaching he had been an officer with the City of Platteville.

Joe Teigen

Grand Chute Police Department - Case Study – Kidnapping & Sexual Assault

Joe is originally from western Wisconsin and has been a police officer with the Grand Chute Police Department since 2013. After working six years as a patrol officer on different shifts, Joe was assigned to a detective position in the investigations unit in 2019. Joe’s additional duties have included field training officer, evidence technician, drone pilot, and mobile device examiner. As one of three detectives for the agency, Joe is actively involved in a wide range of investigations ranging from property crimes to homicides.

John Grassel

Results of a Footwear Evaluation Study Conducted During a Police Training Academy

Basic Crime Scene Documentation

John Grassel is a Senior Forensic Sciences Program Manager at RTI International. He holds an MS in Biomedical Forensic Science from the Boston University School of Medicine, is an IAI Certified Footwear Examiner and Senior Crime Scene Analyst. Mr. Grassel is the past Chair of the IAI Board of Directors and a Past IAI President, as well as a IAI New England Division past President. He is Chair of the International Association of Chiefs of Police (IACP) Forensic Sciences Committee and serves as an affiliate member of both the OSAC Footwear and Tire and Crime Scene Reconstruction Subcommittees. Prior to joining RTI, Mr. Grassel led the Rhode Island State Police Forensic Services Unit.

Katie McCoy

Alternative Light Source Photography

Inadvertently Captured Evidence in Images and Videos

Katie A. McCoy is a Forensic Imaging Specialist at the Wisconsin State Crime Lab and worked as a Crime Scene Response Photographer. She earned a Bachelor of Science in Criminal Justice from the University of Wisconsin – Milwaukee and an Associates in Photography from Milwaukee Area Technical College. Katie has worked in the Forensic Imaging Unit at the Crime Lab since 2016.

Kory Krueger

Kaukauna Double Child Homicide

Kory Krueger has been with the Kaukauna Police Department for 25 years. Kory has
worked as a patrol officer, drug investigator, school resource officer, detective, and is
currently the Lieutenant of Investigations. Lt. Krueger has experience in all types of
crimes including sex crimes, robberies, financial, narcotics, and death investigations. Lt.
Krueger has earned several individual and teamwork Best Badge awards in Outagamie
County related to past investigations. Lt. Krueger has an Associate’s Degree in Criminal
Justice and a Bachelor’s Degree in Leadership and Organizational Studies from UW –
Oshkosh.

Larry Stringham

Evidence Room Audits: It’s not that hard

Developing more Fingerprint information using ALS

Larry has been connected with law enforcement since 1985 when he joined the US Air Force as a Security Policeman. Working with the USAF and later with the Air National Guard, Larry became a certified Police Officer in Little Rock Arkansas. Retuning to Hernando County, Florida, where he was raised, he was hired by the Hernando County Sheriff’s Office as a 911 dispatcher and in 1991 became a crime scene technician. Larry worked here for 6 years, during which time he attended basic and advanced courses in crime scene, arson investigation and fingerprint technology.

In 1997, Larry became a Forensic Technician for the Cape Coral Police Department. At that time, this assignment was a one-man position. He worked hard to grow the department and its forensic section. Being promoted to supervisor of the Forensic Section in 2005, Now retired since 2020 Larry worked hard to increase the Department’s viability by creating latent, computer, video, and lab units within the forensic section. In 2017 Larry oversaw the accreditation of the crime scene/Latent units and the lab to ISO/IEC 17020 standards.

Larry has an Associate’s Degree in Criminal Justice and has testified as an expert in the fields of latent print identification, 10-print identification, and crime scene procedures to include forensic light sources, photography, scene processing, crime scene reconstruction and Evidence procedures and Management. He presently sits on the Board of Directors for the IAI and is the Chairs the Management Committee. He is presently serving as the Conference Educational Planner for the Florida Division of the International Association for Identification (FDIAI) and is a past president of the FDIAI.

Marty Keck

Cellphones In Investigations

Detective Martin Keck is a proven, experienced police detective working in the metro Milwaukee area. With over seventeen years of law enforcement experience, ten of which he served as a detective and five years as a federally deputized task force officer investigating violent crimes in the metro Milwaukee area, Martin has worked hundreds of cases leading to convictions in state and federal court. He has testified dozens of times in court, co-chaired jury trials in state and federal court and has testified as an expert witness.

Martin is certified in conducting forensic examinations of cell phones, as well as mapping cell tower data. He has conducted nearly 500 forensic examinations of cell phones and mapped cell tower data from all of the major cellular service providers in over 100 investigations.

Martin has vast experience in the instruction of law enforcement officers, detectives and analysts. He has instructed hundreds of investigators throughout the United States.

Matthew Corley

eTrace & NIBIN

Industry Operations Intelligence Specialist (IOIS) Matthew Corley has worked for ATF since July 2004 in both the Kansas City and the Chicago Field Divisions. While assigned to each Field Division, IOIS Corley has worked extensively in the Crime Gun Intelligence Centers (CGIC) for both specializing in the eTrace and NIBIN program as well as Crime Gun Intelligence as a whole. IOIS Corley currently serves as the Chicago Field Division eTrace Coordinator. IOIS Corley has presented numerous eTrace/NIBIN and Crime Intelligence Seminars for law enforcement agencies throughout Illinois, Indiana and Wisconsin. IOIS Corley successfully attended the first ever Crime Gun Intelligence Expert Training Class held by ATF in 2018.

Michael Medina

Cryptocurrency: Unraveling the Digital Currency Maze

Michael Medina is a Detective with the Appleton Police Department. He has been with the Appleton Police Department for 17 years serving 3 years as a Detective in the Investigative Service Unit (ISU) and 6 years as a Street Crimes Investigator in the Community Resource Unit (CRU). During his time in CRU, he investigated street level crimes in the areas of drugs, gangs, and prostitution. While in ISU, Detective Medina has investigated a wide variety of crimes to include homicide, attempted homicide, drug overdose deaths, and property crimes. More recently, Detective Medina has focused on financial crimes to include becoming one of the first cryptocurrency investigators to successfully execute a crypto seizure in Northeast Wisconsin.

Nate Weston

Scene Lighting and Murder Mystery

Nate Weston graduated from West Virginia University (WVU) in December 2023 with a M.S. in Forensic and Investigative Science, where his thesis involved assessing how accidental features in forensic footwear change with continued wear. Prior to this, he graduated from WVU with a B.S. in Forensic and Investigative Science with an examiner emphasis, and a minor in psychology. He started with Foster+Freeman as a Technical Sales Specialist around a year ago which involves educating and demonstrating forensic equipment for crime scenes, questioned evidence, fingerprint processing, and trace evidence. Nate is looking forward to meeting new people across the forensic disciplines and is always looking to learn more about the wide range of forensic science fields.

Ronald Groffy

TIPS, EQUIPMENT and HELPFUL METHODS for PHOTOGRAPHING EVIDENCE at the SCENE and AGENCY

Ron has over fifty plus years of professional photographic experience and an Associate
Degree of Applied Science in Photography. Ron was employed for thirty-five years as
the Forensic Imaging Unit Head having a position that encompasses supervising all
imaging activities for the Wisconsin State Crime Laboratory in Madison, Wisconsin. He
was also an active crime scene investigator, covering the State of Wisconsin, and was
responsible for forensically processing homicide scenes, suspicious deaths, fires
involving deaths, hit-and-run fatalities, officer involved shootings and documenting
autopsies of suspected homicide victims. While employed at the crime laboratory, Ron
acquired practical knowledge in crime scene management, scene processing and
evidential photography. This knowledge base encompasses areas of forensic evidence
in the recognition, processing and collection of evidence to include; fingerprints,
documents, firearms, patterned impressions, biological specimens for DNA, drugs and
trace evidence. Advanced instrumental and chemical searching methods are also part of
his training and applied experiences. His forensic knowledge has been expanded
through several specialized courses provided at the F.B.I. Academy in Quantico, Virginia
the Metropolitan Police Institute, Miami, Florida and through the International Association
for Identification’s educational conferences attending workshops and training sessions.

Ron has extensive teaching credentials that encompass both national and international
venues. He has taught throughout the State of Wisconsin for the past forty years and
served as an adjunct faculty member for several colleges, instructing photography,
forensic evidence and the scientific investigation of crime. He was also active with the
National Criminal Justice Training Center in providing a yearly, one-week evidence
technician class, to law enforcement in Indiana. Ron was also one of the lead instructors
of a two-week evidence technician class, offered at Fox Valley Technical College every
year from 1999 through 2024.

He has written monographs on bite mark, fingerprint and crime scene photography, co-
authored several publications of the Crime Laboratory Physical Evidence Handbook, co-
authored numerous scientific papers presented at the American Academy of Forensic

Sciences, and is a contributor to a book covering dental charting and identifications. He
was also instrumental in developing photographic protocols for using invisible spectrum
lighting to document evidence in ultraviolet, infrared, ALS, and LASER.

At the present time, he is an active life member, elected officer (Historian), past president
and past chairman of the board of the Wisconsin Association for Identification, a life
member of the International Association for Identification and a charter member of the
Wisconsin Association for Homicide Investigators.

Scott Lehmann

The Halderson Double-Homicide Landfill Search

Scott Lehmann, a seasoned law enforcement officer with nearly three decades of experience, currently holds the rank of Lieutenant with the Dane County Sheriff’s Office. During his tenure, he dedicated twelve years to the Crime Scene Unit, where he honed his skills as a forensic investigator. Scott is an avid proponent of technological advancements and spearheaded the development of the Dane County Sheriff’s Office’s unmanned aerial vehicle (UAV) program. Scott was instrumental in organizing and facilitating the landfill search as part of the Halderson double homicide investigation.

Scott Simons

Cryptocurrency: Unraveling the Digital Currency Maze

Scott Simons is an active Detective with the Greenfield Police Department where he has been employed for 22 years, a member of the Midwest Cryptocurrency Task Force, team leader of Operation Shamrock (a public and private sector cryptocurrency collaboration), and owner of Criterion Training Solutions teaching law enforcement, prosecutors, and financial investigators. Scott has worked drug and money laundering investigations for 19 years of his law enforcement career which includes being assigned to the Greenfield Police Special Operations Unit and 10 years as a federally deputized Task Force Agent with the Drug Enforcement Administration (DEA). During his tenure with the DEA, he focused on significant financial and cyber investigations domestically and overseas resulting in the seizure of illicit assets in excess of $20mil, to include $2mil in cryptocurrency. Scott has presented various cyber investigative topics at conferences, DEA Headquarters, and to foreign law enforcement on behalf of the U.S. Department of State. Scott is a judicially recognized drug trafficking subject matter expert.

Steve Johnson

Facial Recognition

OSAC Review

Mr. Johnson is a retired law enforcement supervisor with a background in latent print
examination, crime scene investigation, forensic art and facial identification. He is a Senior
Instructor for Ideal Innovations, an industry leader in Facial Examination Training. Mr. Johnson
is a Past President and Board Chair of the IAI, a member of Forensic Art Certification Board and
is the current Chair of the Facial Identification Committee. He is the former IAI representative to
the Organization of Scientific Area Committees for the Forensic Sciences (OSAC), serving as
Chair of the OSAC Forensic Science Standards Board (FSSB) from 2017 to 2020. In addition to
his duties with the IAI he is currently serving as a member of the OSAC Facial Identification
Subcommittee. He is representing OSAC as a Standards Implementation Advocate.

Wayne Treep

Obliterated Serial Numbers

Detective Sergeant, Wayne Treep began his career with the West Allis Police Department in 2005. Wayne was promoted to Patrol Sgt. in 2016 and to Detective Sgt. In the Forensic and Technical Services Unit in 2017.

Some of Wayne’s responsibilities including major crime scene processing, processing of physical
evidence to include firearms, latent fingerprints (fuming) and serial number restoration. Wayne also been trained Bullet Trajectory Reconstruction and is also a ATF NIBIN technician.

Wayne is also trained in vehicle forensic processing with Berla forensics and crime scene mapping with Trimble 3D laser scanner. Wayne is also the departments Forensic examiner, part of the ICAC taskforce and part of the M.A.I.T (Milwaukee Area Investigative Team) for OIS incidents.