Minn. police seeking motive for random shootings that left boy, 9, dead: 'He was just a baby'

A minivan with a shot out back window sits in the parking lot of a Rainbow Food in Oakdale, Minn. on Monday, Feb. 11, 2013. Oakdale police say a 34-year-old Oakdale man opened fire randomly at passing vehicles near a Rainbow Foods store about 6:10 p.m. Monday. The boy and his 39-year-old mother were struck in one vehicle. A 68-year-old woman in another vehicle was shot in the hand. All were taken to Regions Hospital. Stark says the boy died of his injuries. The women are expected to recover. The suspect was arrested several blocks away Monday evening, Feb. 11, 2013. (AP Photo/Pioneer Press, Ginger Pinson) MINNEAPOLIS STAR TRIB OUT, MAGS OUT, MANDATORY CREDITThe Associated Press

Police are trying to determine why a 34-year-old man randomly shot at passing vehicles in a suburban St. Paul neighborhood, wounding a female driver and killing her 9-year-old son.

A witness tells The Associated Press that the man identified by police Tuesday as Nhan Lap Tran of Oakdale, was nonchalantly walking down the block the night before when he began firing.

Nine-year-old Devin Aryal of Oakdale was killed. His mother, 39-year-old Melissa Aryal, was shot in the arm. A woman in another vehicle also was injured, but was expected to survive.

Police Chief Bill Sullivan says it appears Tran legally owned the handgun used in the attack, and that Tran has no apparent history of mental health issues.

Prosecutors were expected to file charges Wednesday.