PORTLAND, Ore. — Police here Saturday morning arrested a suspect in the shooting that injured three people outside an alternative high school.

Authorities said they stopped a vehicle about 1:30 a.m. Saturday and arrested a 22-year-old man. A handgun was found in the vehicle.

Police were searching an apartment about half an hour later as part of the investigation. The apartment is about five blocks east of the shooting near Rosemary Anderson High School.

Detectives are investigating and will release the suspect’s name and charges after he is booked into the Multnomah County Jail.

Witnesses told police there may have been a dispute outside the high school on Friday, just before the shooting occurred at a street corner.

The assailant and two other people fled, and the wounded students went to the school for help, a police spokesman said. A 16-year-old girl was critically wounded while two males were hospitalized in fair condition. Another girl was grazed by a bullet.

“Based on the investigation thus far, the shooting appears to be gang-related,” Sgt. Pete Simpson said Friday night in a statement.

Police gang investigators “feel comfortable saying this is a gang-related shooting based on some of the people involved,” Simpson added in an interview. Simpson declined to say which victims might be linked to gangs.