UPDATE: 8:23 a.m. Thursday

Kent Police continue to look for the gunman Thursday morning, according to Lt. Pat Lowery with the Kent Police Department.

Detectives have interviewed several people who had been on the bus and are looking at evidence recovered there, Lowery said.

The shooting victim is in critical condition at Harborview Medical Center in Seattle.

ORIGINAL POST: 9:59 p.m. Wednesday

Police were searching in the East Hill-Meridian area Wednesday night for the person who twice shot a 30-year-old Metro bus passenger in the torso.

The victim, a Sea-Tac man, was taken to Harborview Medical Center, Kent police spokesman Pat Lowery said, and his condition was unknown Wednesday night.

According to Lowery, a Route 169 bus driver heard a “”commotion”” between two men in the back of the bus at around 6 p.m. as it traveled in East Hill-Meridian near Kent.

The two had argued, witnesses told police. One man seemed to be getting off the bus when he suddenly pulled a gun. The bus was approaching the 20600 block of 108th Avenue Southeast when the driver heard gunshots.

The victim appeared to have been shot twice in the torso and was knocked unconscious. The shooter then headed to the front of the bus, pointed the gun at the driver and demanded to be let off, Lowery said.

The driver pressed a 911 panic-alarm button before opening the doors, and the shooter fled across the street to an apartment building, Lowery said.

Kent police, Renton police and King County sheriff’s deputies responded to the scene four minutes later and set up a search perimeter in the area. A canine search unit found the weapon the shooter may have used, but police did not find the shooter himself. They are asking for the public’s help.

Witnesses described the shooter as being about 5-foot-7, black and wearing a black and red NASCAR-style jacket, Lowery said. He was estimated to be 17 to 22 years old. Lowery asked that anybody with information about the shooting contact Kent police at 253-856-5800.

Lowery said the shooting was likely not a spontaneous act, given witness reports that the two men had gotten into an argument just beforehand.

According to 2009 statistics from King County, the latest available data, a Metro bus driver is threatened with a weapon or in need of medical care following an assault an average of once a month. In 2009, there were 146 assaults on Metro drivers, ranging from spitting to attacks resulting in serious injuries.

This latest incident recalls other violent Metro bus incidents in recent years. In January 2010, on Metro Route 124 in Tukwila, a 15-year-old punched and knocked out a Metro bus driver while two other teens beat down the rear door because the driver refused to let them off.

Last August, while riding the Route 7 bus a 10-year-old boy accidentally shot himself in the arm during a struggle with an older boy.

In 2007, two 17-year-olds were assaulted by an angry mob of 25 to 30 teens shouting profanities on the Route 7 bus; they were punched and threatened both on and off the bus in Columbia City.