MADISON, Wis. (AP) — Gov. Scott Walker has signed a bill that requires Wisconsin police departments to use outside investigators to probe officer-involved deaths. The measure passed both the Assembly and Senate on voice votes earlier this year. The bill's chief sponsors, Reps. Chris Taylor and Garey Bies, issued a joint statement Wednesday saying the governor has signed the measure. The bill comes in the wake of several high-profile officer involved deaths across the state in recent years. Supporters say it will alleviate concerns about investigators from the same department covering up their friends' misconduct. Smaller departments routinely rely on outside agencies to investigate officer-involved deaths. But the state's two biggest departments, Madison and Milwaukee, investigate their own officers.