Officer Robert Tatman was working the overnight shift that Friday night. In his last call to the base, he said he was pulling someone over.
"I think less than five minutes after that, an unknown voice came on the police radio using his squad car radio and called in that there was a dead policeman laying beside the squad car on Church Street," said Zane Ziegler, who works for the Champaign Police Department.
Investigators went to work to try to piece together clues from the scene.
"His gun and flashlight were laying near his feet," said Ziegler. "So that's about all there was at that time. There wasn't a lot of other evidence. Nobody saw anybody leaving the area."
Over the years, dozens of investigators have been assigned to the case. They've uncovered many leads but still don't know who pulled the trigger. It's a situation police have seen once before.
"We've only had one other officer killed in the line of duty. 152 years now, so it was pretty unusual," said Ziegler. "So, you train against those types of things and try to follow procedures and that's all you can do."
One of the places officers now train is a room was named for Officer Tatman. Every May for Law Enforcement Week, people gather to remember a man who gave his all for the people of the city.
"We try to remember each year, remind the younger officers," said Ziegler. "We try to keep it in mind all the time."
Usually officers will call in a description of the car and the license plate number during a traffic stop. That night, Tatman didn't. Investigators said they don't know why.