NIAGARA FALLS—Police investigators say they have found a key witness in an assault July 17 on the patio outside Player’s Tavern on Niagara Street.

A woman who had called police after the assault, then left town, returned to the bar Tuesday, Capt. William Thomson, chief of detectives, said. The bartender immediately called police, and she and two of her friends were interviewed.

The victim, Christopher J. Scrivano, 47, of Mason Drive, was still unconscious in critical condition Thursday in Erie County Medical Center, Buffalo. Police said he was hit in the face and fell backward onto the concrete, causing a gaping head injury. Police said they still don’t have a motive for the attack.