The medical examiner has determined that the two victims and the gunman in Friday's deadly supermarket rampage in Old Bridge, N.J. died of single gunshot wounds.

In a report released Saturday, the medical examiner determined 18-year-old Cristina LoBrutto and 24-year-old Bryan Breen both died from gunshot wounds when 23-year-old Terence Tyler shot them. 

Tyler, who then turned the gun on himself, died of a single gunshot wound to the head. 

Police tapes also released Saturday shows emergency dispatchers called for officers minutes after the shots were fired at the Pathmark supermarket.

"There's a female who is locked in the storage room right now, she said she's still hearing shots being fired," the dispatcher says. "And my partner has somebody on the line that's back in produce."

A responding officer asks, "When was the last shot fired?"

Later, an officer at the scene states, "Headquarters, we need first aid immediately on the perimeter." 

Tyler, an ex-Marine, killed his two coworkers and himself just before 4 a.m. after bursting through the glass windows of the Pathmark store dressed in camouflage, brandishing an AK-47 and an automatic handgun. A third weapon --a shotgun -- was later found in Tyler's vehicle. 

Prosecutor Bruce Kaplan said it did not appear LoBrutto and Breen were specifically targeted, but were in the general line of fire. 

Tyler had worked at the store for around two weeks before the shooting. Investigators were reviewing security footage from the rampage and attempting to find out where he had obtained his arsenal of weapons.

They were also looking into whether Tyler's AK-47 jammed after he fired 16 shots, since he had two rounds of ammunition on him in the store. 

Tyler, formerly of Brooklyn but living in Old Ridge, served in the U.S. Marine Corps from 2008 to 2010, a Marines spokesman said. Tyler was a lance corporal and rifleman, who received two medals and never served overseas, the spokesman said.

Tyler may have had a history of depression or mental illness, a law enforcement source said.

MORE: Pathmark Gunman Changed After Mom Died, Cousin Says

At a vigil held Friday for the two victims at Old Bridge High School, LoBrutto and Breen were both remembered for their humor and outgoing personalities. LoBrutto, who was a horn player in the school band, had graduated this year; Breen graduated in 2006. 

MORE: Stunned Community Mourns Pathmark Shooting Victims at Vigil

Get the latest from NBC 4 New York anytime: iPhone/iPad App | SMS Alerts | Twitter | Facebook | Google+ | Instagram | RSS