The police chief of Portland, OR, is retiring as authorities continue to probe a hunting accident in which he mistakenly shot and injured a friend, the mayor of Portland announced Monday.

Chief Larry O'Dea, 54, was vacationing in eastern Oregon in April when he accidentally shot and injured a close friend with his .22 caliber rifle, authorities say.

But Harney County Sheriff Dave Ward, who initially investigated the April 21 shooting, was first told that the injury was self-inflicted, according to the sheriff's department. About a month later, Mr. Ward learned that Mr. O'Dea was involved in the incident, reports the Wall Street Journal.

Mayor Charlie Hales said at a Monday morning press conference that Mr. O'Dea "recognized the strain" on the police department and "the need to move forward." Mr. Hales praised the efforts of Mr. O'Dea who had been with the department for three decades, but said that that the city now needs to "start another chapter of progress and change."

The new chief will be Mike Marshman, a Portland police captain who Mr. Hales said has been driving the reforms at the department.