A gruesome act of violence shook a Pennsylvania community on Sunday afternoon when a man allegedly stabbed his mother to death. Police found the woman dying on the street. At approximately 5:38 p.m., police responded to a call on the 100 block of Liberty Avenue, where a man was reportedly stabbing a woman. The suspect, Brian Rebold, 38, called 911 himself to report the incident, and several neighbors witnessed the attack. Read: Texas Mother Charged With Murder After Leaving Infant In Hot Car For Hours Officers arrived to find Diana Rebold, the suspect’s mother, lying unresponsive in the street…