(AP) — Prosecutors say they’ve dropped murder and assault charges filed against a man after a shooting on the pedestrian bridge that connects Omaha with Council Bluffs, Iowa.

Douglas County Attorney Don Kleine said Thursday that witnesses were evasive or otherwise uncooperative with investigators and prosecutors, so the case against 24-year-old Terrece Cox became impossible to prosecute. Cox’s trial was scheduled to begin on Monday. He has maintained his innocence throughout the investigation.

Cox was charged with second-degree murder and other charges after the May 29 shooting death of 26-year-old Shamari Richards on the Bob Kerrey Pedestrian Bridge. The other people were wounded.

Billy Kellogg was charged with being an accessory to a felony. It’s unclear whether his charges will be dropped as well.