Witnesses said Chance Baker was shot by police after waving a BB gun around the parking lot.

Portland police examine the scene where an officer shot Chance Baker at Union Station Plaza on Saturday.

A rifle and a 40-ounce bottle of malt liquor -- under a red bandana -- lie at the scene where Chance Baker was shot by police at a strip mall on St. John Street.

Portland Police Chief Michael Sauschuck, right, speaks to another officer at the scene of an officer-involved shooting at Union Station Plaza on Saturday.

A sign at Coastal Trading and Pawn, the shop at Union Station Plaza in Portland where, according to witnesses, Chance Baker bought a pellet gun before being shot by police.

Police document the scene of the shooting in the parking lot of Union Station Plaza.

Police say the attorney general's office is investigating the shooting.

Investigators prepare to set up survey equipment at the shooting scene on St. John Street on Saturday.