OVERLAND PARK, Kan. — Never one to keep his hatred to himself, Frazier Glenn Cross for decades sought out any soapbox to espouse his white-supremacist beliefs, twice running for federal office with campaigns steeped in anti-Semitism.

Yet there’s scant evidence the Army veteran and retired trucker with Ku Klux Klan links ever resorted to violence before Sunday, when authorities say he opened fire with a shotgun and pistol outside a Jewish community center and retirement complex near Kansas City. None of the three people killed turned out to be Jewish.

The 73-year-old Cross, who shouted a Nazi slogan at television cameras when arrested minutes later, has been jailed awaiting charges that investigators said could come as early as Tuesday. At some point, a federal grand jury is expected to review the slayings, which authorities now deem a hate crime.