PITTSBURGH — Pittsburgh police are trying to find a man who stabbed or slashed three people downtown after a woman he knew fought with one of the victims.

Police haven’t released the names of anyone involved near a 7-Eleven store about 11:20 p.m. Thursday. Police say the women argued inside the store, then began fighting outside it.

That’s when police say a 27-year-old man punched the woman the suspect knew in the face. That prompted the suspect to use brass knuckles with a knife attached to punch the other man in the face then stab a 29-year-old woman who had been fighting and another 32-year-old man who intervened.