After mortally wounding his former girlfriend and then confessing that he had caused the deaths of two of his children, the 29-year-old son of a Chester City patrolman was shot and killed by police, Delaware County authorities said yesterday.

Aaron Michael of Chester was killed shortly after midnight outside the house he shared with his father, Officer John Michael, who was away on vacation.

The shooting was the culmination of a deadly series of events that began about 11:30 p.m. Monday, when Aaron Michael confronted Andrea Arrington in Ridley Township. Arrington, the mother of Michael's 2-year-old son, Aaron Jr., had come home from work and was walking on Constitution Avenue to pick up her son from a babysitter.

The two began arguing about a protection-from-abuse order that Arrington, 23, had filed July 2. In the order, Arrington alleged that Michael had pushed, slapped, choked, and kicked her in June. Michael was arrested last week for violating that order.

Michael pulled out a gun and shot Arrington, who fell to the ground, said Detective Sgt. Scott Willoughby of the Ridley Township police. Michael then stood over her and continued firing. Arrington was hit about 11 times, Willoughby said.

Before she died, Arrington told authorities that Michael had shot her. She was taken to Crozer-Chester Medical Center, where she underwent surgery most of the night. She died yesterday at 7:21 a.m.

Michael shot Arrington with a .40-caliber Heckler & Koch semiautomatic pistol that was his father's duty gun, according to Willoughby.

Delaware County District Attorney G. Michael Green said that the gun Aaron Michael used had been stolen from a locked room inside the home in Chester, but that he wasn't sure it was the father's service gun.

After the shooting, Michael fled to his house on 23d Street. Detectives attempted to coax him out. Michael told police, who contacted him on his cell phone, that he planned to kill himself.

Inside the house, Michael phoned two friends and admitted that he had earlier caused the deaths of two of his children, Green said.

While in Michael's custody, Lamar Patrick, 4, died in September 2005, and Alijah Townes, four months, died in July 2007.

The Delaware County Medical Examiner's Office had ruled that the causes of death were undetermined. Lamar died overnight in what could have been a choking death, Green said. Alijah had tested positive for meningitis.

The District Attorney's Office and Chester police had questioned Michael about the deaths, and the investigation was ongoing. But the most concrete piece of evidence came early yesterday when Michael talked with two friends, Green said.

After the conversations, Michael came out of the back of the house, where Chester officers were waiting, Willoughby said. Michael raised his gun toward one of the officers, who then shot Michael in the chest.

Authorities declined to identify the officer who fired the shot, but said he had been assigned to administrative duty while the shooting was under investigation.

Michael was pronounced dead at Crozer-Chester Medical Center at 12:36 a.m.

Michael, who court records say worked at a Taco Bell in Media, had earlier been charged and pleaded guilty to retail theft, criminal conspiracy, and theft by deception in Delaware County. He was sentenced to probation. He was found not guilty in March 2002 of indecent assault and voluntary deviate sexual intercourse.