The shooting rampage at the Fort Hood US Army base last week started with an argument over leave and lasted eight minutes, with the suspected shooter getting in and out of his car as he fired on soldiers he worked with and others who happened onto his path, investigators said on Monday.

Specialist Ivan Lopez, 34, drove his car slowly through the central Texas base as he carried out the rampage. He got out at two facilities, including the place he was assigned, fatally shooting three people and wounding 16 more before turning the gun on himself, Christopher Grey, spokesman for the US Army Criminal Investigation Command, told a news conference.

The shooting in which three people were killed and 16 wounded was the second deadly rampage at the base, one of the largest US Army posts in the country, in five years. It raised questions about protecting soldiers at home and caring for troops battling mental illness, such as Lopez.

The incident started with the argument at an administration building, Grey said as he filled in some of the details of the shooting spree.

"Within minutes of the altercation, the subject brandished a .45 caliber, semi-automatic handgun and fired multiple rounds, killing one soldier and wounding 10 additional soldiers," Grey said.

Lopez then got into a car, fired at two soldiers walking past, wounding one, and went to the motor pool office where he was assigned.

He shot and killed one soldier in the office and wounded two more in a vehicle bay before getting back into his car and shooting through the windshield of a moving vehicle, wounding another person, Grey said.

Lopez then went to a medical brigade building, killing one soldier and injuring two more before getting back in his car and pulling into a parking lot. And finally he was confronted by a female military police officer, and shot himself in the head.

Reuters