ST. JOSEPH — His specialty is accident reconstruction. But his side gig is evidence construction. 

Detective Sgt. Thad Chartrand is the team leader for the Berrien County Sheriff’s Accident Reconstruction Unit. But recently, his work has made its way into Berrien County courtrooms where it has served as evidence in trials.

A replica of a marijuana grow room was used as evidence in one murder case; and a mock-up car interior was used in another case. Both cases resulted in convictions.

Chartrand, also a crime scene technician, said the idea behind the life-sized props is to demonstrate and confirm what investigators and other witnesses say in court. 

“Jurors are getting to where words and pictures are not enough. People need to see if the way a defendant says something happened just isn’t possible,” Chartrand said. “I’m hoping these helped.”

In the case of the marijuana grow room, John Lewis of Niles was convicted of killing his wife, Carla Lewis. He had told police she was shot by an intruder while they were in their marijuana grow room downstairs, and that he could not reach to grab the intruder’s gun. But based on the size of the grow room and location and size of the doorway, investigators knew that could not be true. Instead of telling the jury that, Berrien Assistant Prosecutor Gerald Vigansky decided to show them, and asked Chartrand for help.

Measurements were taken at the actual scene by Detective Sgt. Sean Soulard, who helped Chartrand build the replica of the room using those measurements. The room had to be taken into the courthouse in four pieces and was re-assembled in the courtroom during a break in the trial.

The replica of the interior of a 2013 Hyundai Elantra was used recently in the case of William Edwards, convicted of second-degree murder in the shooting death of his longtime partner, Novena Mathis. Edwards shot her to death in her car.

At the request of Berrien Assistant Prosecutor Jane Wainwright, Chartrand built the car interior using seats donated by an area auto body shop and it was used in court to demonstrate that the positioning and movements of Edwards and Mathis in the vehicle as claimed by Edwards could not be true. 

Chartrand said in both cases, it was the prosecutor’s office that approached him about building the props, and he got the blessing of his boss, Sheriff Paul Bailey. He said the grow room and the car replica together cost less than $500.

Chartrand was a Lincoln Township police officer from 1993-2012, and worked as an accident reconstructionist. He joined the Berrien County Sheriff’s Office in 2012 and has been leading the Accident Reconstruction Team since 2018.  

When he was in high school and college, he worked in construction during the summer, helping to explain his knack for swinging a hammer.

Contact:, 932-0359, Twitter: @HPSwidwa