DALLAS - A MAN suspected in a series of rush hour shootings near Dallas is a former Utah state trooper wanted on burglary and robbery warrants who apparently shot himself after a standoff with police, authorities said on Tuesday.

Brian Smith, 37, killed at least one of the victims of Monday's shootings, Dallas police Lt Craig Miller said. Investigators tied Smith to a killing in Dallas because by matching the bullets found at the standoff, he said.

'We feel safe in saying (Smith) ... was the shooter,' Lt Miller said.

Dallas police declined to comment on a second death in neighboring Garland, where the standoff took place, because it was out of their jurisdiction.

Garland police spokesman Joe Harn said his department has not been able to make a definitive connection between Smith and the killing there, but acknowledged that he fit the description of the highway shooter: a balding, 40ish white man.

'We certainly hope it is him,' Mr Harn said. 'But we are going to have to see more concrete evidence.' Two people were shot and killed and another person was injured by broken glass in four shootings along or near a Dallas-area highway Monday evening. Police believe the victims were selected at random.

Smith was in critical condition on Tuesday night at a Dallas hospital from a self-inflicted gunshot wound. Police said he shot himself in the head early on Tuesday morning after a brief standoff more than six hours after the shooting spree ended.

Smith had been a Utah state trooper since 1996 but retired in May because of 'personal issues,' said Sgt Jeff Nigbur, a spokesman for the Utah Department of Public Safety.

The crime spree appears to have begun in Garland, where a man police identified as Smith jumped over a pharmacy counter at a grocery store and stole Oxycontin pills.

Minutes later, the first shooting happened in Garland when a driver pulled up alongside a small Nissan stopped at a red light and began shooting, Mr Harn said. The Nissan's driver, 20-year-old Jorge 'George' Lopez, was killed.

Minutes later on the same highway, a gunman shot and killed 42-year-old William Scott Miller, the driver of a United Van Lines moving truck, police Lt Craig Miller said.

After the shooting of Miller, another semitrailer was fired upon a kilometre away on the same interstate. The driver, 46-year-old Gary Roberts, was injured by debris and glass but not struck by any bullets. His right eye was hit by shattered glass and he needed several stitches in his fingers, said Bedford Wilhite, who works with Roberts at Dugan Truck Line. -- AP