A man who tried to enter a teenage girl's bathroom stall was confronted and killed by the girl's father, officials say.

According to Phoenix police, around 11:30 p.m. on August 2, 40-year-old Melvin Harris went to the QuikTrip near Dunlap and 19th avenues to pick up his teenage daughter and her friends.

A man, who would later become the victim, approached Harris' car in the parking lot and asked for money. Harris gave him some money, and the man went into the QT.

Harris was later informed that a man tried to enter the bathroom stall his daughter was using. The teen told an employee, who in turn alerted an on-duty security guard.

Leon Armstrong exited the store and was pointed out to Harris, who realized it was the same man he had given money to earlier. Harris went into the store and told the security guard that, "he needed to take care of the situation, or [Harris] would do it himself." The guard reportedly told Harris he would handle it.

According to witnesses, Harris later approached Armstrong and punched him in the face. Witnesses also reportedly told police that Harris stood over him, hitting him in the face several more times. He also allegedly kicked and stomped on him.

Harris then left the area. Police identified and located Harris at his home nearby.

He reportedly told police that Armstrong punched him first, hitting him in the neck. He denied striking the man when he was down.

Armstrong was taken to the hospital with a broken nose and brain injuries. He later died.

Armstrong's sister said, "He didn't have to take my brother's life when he was down on the ground. He should have just called the police. I understand you want to defend your daughter, I totally get that I have daughters myself, but the way you went about it was totally wrong."

An account has been set up to help the family with funeral expenses.

Harris is facing charges of second-degree murder. He has prior arrests for arson and domestic violence.