WASHINGTON－A former sniper in the United States' military wearing full body armor fatally shot four people, including a mother and her 3-month-old baby, in Florida. Officials said on Sunday he later engaged in a massive gunfight with police officers before he was wounded and surrendered.

The shooter was identified as Bryan Riley, a 33-year-old former US Marine. At a news conference, Polk County Sheriff Grady Judd said Riley also wounded an 11-year-old girl who had undergone surgery for seven gunshot wounds.

Riley engaged in a shootout in Lakeland with police before giving up. He had no connection to the victims. While being treated in hospital for his own gunshot wound, Riley jumped up and tried to grab a police officer's gun before being subdued again.

A veteran of the wars in Iraq and Afghanistan, Riley was working as a bodyguard and security guard. His girlfriend of four years told investigators that he has post-traumatic stress disorder and occasional depression.

About a week ago, his mental health worsened and he told his girlfriend he had started speaking to God.

"He said at one point to our detectives, 'They begged for their lives and I killed them anyway'," said Judd during a second news conference.

Riley also told the deputies that he was high on methamphetamine.

The shooter first appeared at a house where the shooting occurred on Saturday night, making nonsensical statements, but left by the time police responded.

He returned early on Sunday morning, killing a 40-year-old man, a 33-year-old woman and her baby boy. At the home next door, he also killed the 62-year-old mother of the woman.

Deputies responding to reports of two volleys of automatic gunfire arrived to find the suspect unarmed outside, wearing camouflage and body armor. Riley then went back inside and "we heard another volley, and a woman scream, and a baby whimper", Judd said.

A gunfight ensued before he came out unarmed and was arrested.

"It would have been nice if he would have come out with a gun. ...We would have shot him up a lot. But he didn't because he was a coward," Judd said. "Prior to this morning, this guy was a war hero. He fought for his country in Afghanistan and Iraq. And this morning, he's a coldblooded killer."

At the hospital's emergency room, police officers had to fight off Riley who tried to snatch an officer's gun. He was ultimately tied down and medicated.

Riley is expected to recover and will be transferred to jail to face charges.

Agencies - Xinhua