A mentally challenged man who was singing when he boarded a SEPTA bus in Delaware County on Tuesday, was stabbed in the back allegedly by an enraged passenger who believed the cross-eyed victim was staring at him.

Leonard Williams, 59, of Ridley Township, has been charged with attempted homicide, recklessly endangering another person and related crimes for the mid-afternoon assault.

Williams was on the Chester-bound bus when the 27-year-old victim boarded with his mother about 3 p.m. at MacDade Boulevard and Monta Vista Avenue, in Ridley Township, the affidavit said.

The victim was singing, and, according to police, somewhere along the route he looked at Williams, who repeatedly asked what the man was staring at, only to be met with a smile.

" 'If you keep looking at me, I'll hurt you and your white friends,' " Williams told the victim, according to witness reports in the affidavit. "You better look the other way with your crooked eye or I'm gonna stab you."

It was unclear to what friends Williams was referring.

Witnesses told police that Williams then brandished a knife and spouted profanities at the victim and the bus driver, who had asked if the two needed help.

The victim told his mother he was scared and asked to get off at the next stop, the affidavit said.

As they got off the bus at MacDade Boulevard and Bullens Lane, Williams followed, pushed the victim off the bus and pulled out a knife with a 5-inch blade, and stabbed the victim once in the back, Ridley Township Detective William Henderson said.

The victim toppled to the ground, and Williams ran away and hid in a nearby home, on Crum Creek Drive near Dorrett Street, where he was later apprehended by police, according to court documents.

The driver kept the bus at the stop and waited for police to arrive. Several people on the bus came forward as witnesses, Henderson said.

The victim was taken to Crozer-Chester Medical Center, where doctors found that the stab wound had caused the victim's lung to collapse. He remained at the hospital last night in stable condition, Henderson said. *