(AP) — Hundreds marched peacefully in Washington state's capital city to protest a police shooting that wounded two unarmed stepbrothers suspected of trying to steal beer from a grocery store. Brad Watkins, chief deputy of the Thurston County Sheriff's Department, said two skateboards were recovered from the shooting scene and an investigation will likely take three to six weeks. The crowd of demonstrators rallied first at a park, then marched about a mile to a building that houses the Olympia police headquarters and City Hall. Donald encountered two men with skateboards who fit witnesses' descriptions, and moments later, he radioed in that shots had been fired, the police chief said. In radio calls released by police, Donald calls dispatchers once he spots the men, and again to report that he fired shots. The police chief said Donald wasn't injured but an officer "has the right to defend himself" if a suspect wields an object that could be used as a deadly weapon. The shooting follows a string of high-profile killings of unarmed black men by police, including Michael Brown in Ferguson, Missouri, and Eric Garner in New York City, which set off weeks of protests and a national "Black Lives Matter" movement that has gained momentum across the country.