Police arrested Charles Edward Turner, 51, in the 2 pm incident on Saturday, police said. He faces several charges, including attempted criminal murder and four counts of aggravated assault, the records show. He is being held at Allegheny County Jail.
The boy was taken to the hospital in critical condition and was upgraded to the stable, KDKA reported, citing the criminal complaint.
Police say they do not know of any relationship between the boy and Turner, KDKA reported.
CNN was unable to identify a Turner attorney.
Two McDonald’s employees stepped in to help the boy, Cara Cruz, deputy public information officer for the Pittsburgh Department of Public Security, told KDKA.
“He was with his family, he was in line, they had just arrived for something quick,” Cruz told KDKA.
The reason remains unclear and the investigation is ongoing, police said.
Detectives from the Major Crime and Crime Scene units are reviewing the scene, analyzing video evidence and talking to eyewitnesses, the Pittsburgh Department of Public Security posted.