Illinois law officials hit a dead end in their investigation into the killing of Lt. Charles ‘Joe’ Gliniewicz. According to a report from Fox, the investigation stalled this Tuesday after a week of searching for evidence surrounding the brutal murder.

Three individuals were taped by a security camera around the time of Gliniewicz’s death in Fox Lake, and were also seen in the area where the officer was found dead, but have been ruled out as suspects. The group initially fit the description of the people Gliniewicz was chasing as he was last heard on the radio.

Lake County Major Crime Task Force Commander George Filenko revealed on Tuesday that investigators had located the three people from the security footage provided by a resident, interviewed them, and confirmed that they were not involved with the death of the lieutenant.

While video and time-stamped evidence absolves the three initial suspects, Filenko revealed that there was DNA found at the scene that had not yet been matched. The Commander would not reveal the type of DNA discovered at the scene, but had confirmed that there was a DNA transfer.

Investigators are hopeful that forensic evidence will lead them to the lieutenant’s killer. There was no dashboard camera in Gliniewicz’s car at the time of the killing, and despite the fragile DNA lead, police are thoroughly stumped at this point.