Authorities have acquired more videos that they believe are "relevant" to the fatal shooting of an Illinois police officer, an official said Friday.
Fox Lake Police Lt. Charles Joseph Gliniewicz was found shot to death on Tuesday morning in a remote area near an old cement plant, police say.
A number of sources, including Lake County Department of Transportation, turned over video to authorities overnight, Lake County Major Crimes Task Force Commander George Filenko said Friday. The video is from local intersection cameras "that are key to that exact location," he said.
"We are still reviewing a substantial amount of video. We've now coordinated with the FBI, who have the ability to chronologically put together the video segments," Filenko said, adding that the footage contains images from before and after the time of Gliniewicz's death.
News of the videos came a day after Filenko said a resident had turned over home surveillance footage that showed individuals who matched the description of the three suspects authorities are looking for. That tape was still being analyzed Friday.
Related: Police Believe Suspects in Illinois Cop's Killing Are Familiar With Area
"Now we've acquired several more videos that we believe are even more relevant," he said Friday. "I think we’re optimistic about all of these videos right now because they all come together chronologically."
According to Filenko, Gliniewicz, a veteran officer, saw three men in an overgrown field and stopped to question them at 7:52 a.m. Tuesday morning. He radioed for backup a few minutes later, but by the time officers arrived, Gliniewicz was found dead, police said.
Related: Illinois Cop Killer: Nanny Charged With Falsifying Sighting
Gliniewicz had provided a brief description of the men he was pursuing: two white men and one black man.
On Friday, Filenko said that based on the new videos, "we have images of people that we believe are subjects that we'd be interested in talking to."
It appeared those individuals left the area on foot, he added, but said it wasn't clear whether they got into a car after their initial escape.
Officials also said a $50,000 reward is now being offered for information leading to an arrest in the case.
The village of Fox Lake is about 60 miles north of Chicago.
