The child was holding his grandmother’s hand as they were walking to church Oct. 17, when the incident occurred, the Philadelphia Police Department said.
He allegedly threw a bag at the woman and claimed the boy was his son.
Footage of the encounter appears to show the suspect trying to grab the child.
The grandmother told Fox affiliate WTXF-TV she tried to fend off the attacker by throwing her keys at him. He continued to follow and yell at them until they got to the church.
“By the time I got into church my heart was going. I was a nervous wreck. I was crying,” she told the news outlet.
The suspect was described by police as a Black man in his mid 30s, who is 5 feet, 11 inches tall.