PHOENIX -- Two teenagers arrested in connection with the death of an Arizona Department of Corrections officer whose body was found early Sunday in the median of a roadway admitted to planning a carjacking to go to a party in Goodyear, according to newly-released police documents.

The juveniles, Felix Vasquez, 16, and Benjamin Cannon, 15, were arrested Wednesday and booked on charges of first-degree murder and armed robbery in connection with the shooting death of Bradley Jay Gerrard, 28, a resident of the Tartesso neighborhood in Buckeye.

They both detailed the incidents of that night, pinning each other as the gunman, the document said.

One of the teens laid in the middle of the road and when Gerrard got out of his car to see if the teen was OK, the other teen walked up with a shotgun and shot Gerrard in the chest, according to court documents.

Police are still trying to figure out who pulled the trigger.

Detectives said Vasquez told them they dumped a baby seat and stroller from the vehicle in the area of McDowell Road and Miller Road. Vasquez said they dumped the vehicle in the desert south of Tartesso and lit it on fire before walking back home, the court document said.

Gerrard had been a corrections officer since 2004 and was assigned to the Arizona State Prison Complex-Lewis. His body was found just after midnight Sunday in a median along Tartesso Boulevard near Bruner Road.

Police said Gerrard had been shot at close range. Officers found his partially burned vehicle several miles away.

Police said Gerrard left his home around 11 p.m. Saturday to buy an air mattress for a visiting family member. Detectives said he was attacked on his way home from Wal-Mart.

Several Arizona Department of Corrections canine tracking teams successfully located additional physical evidence that led to the arrest of the two juveniles within days of Gerrard's murder, police said..