His standoff with police followed by his shooting himself, and the matching bullets found from the place crime and the standoff - all these are evidence enough to suggest that Brian Smith, a former Utah state trooper, was involved in the rush-hour shootings Monday in Dallas-area, in which two motorists were killed. Moreover, he fits the description of the highway shooter - a balding, 40ish white man.

According to Dallas police, Smith, 37, is a suspect in the shootings on Interstate 635, and his possible involvement is also being investigated in two Garland crimes - which began earlier Monday with the robbery of a Kroger pharmacy, followed by fatal shootings at random at Jupiter Road and Marquis Drive.

Joe Harn, a Garland police spokesman, said Tuesday that before the investigators link Smith with the Garland shootings, they are waiting for results from their own ballistics testing. Harn added: "We're testing the bullets found in his vehicle with the other shootings. It's just a part of our investigation because of how close in time the events happened to each other."

The man wanted on burglary and robbery warrants, Smith, was reportedly in critical condition at a Dallas hospital Tuesday night, due to the self-inflicted gunshot wound. The police said Smith shot himself in the head early Tuesday morning - almost six hours after the shooting spree ended - following a brief standoff with a SWAT team.

Sgt. Jeff Nigbur, Utah Department of Public Safety spokesman, said that Smith, who had been a Utah state trooper since 1996, had retired in May citing "personal issues."