A transit police officer who was shot and critically injured during a shootout with the Boston Marathon bombers is retiring.

Richard Donohue Jr. nearly died during a chaotic gun battle in Watertown four days after the 2013 bombing as police closed in on the suspects, brothers Dzhokhar (joh-HAHR') and Tamerlan Tsarnaev (TAM'-ehr-luhn tsahr-NEYE'-ehv). A 2015 report found it "highly likely" that Donohue was hit by friendly fire.

The bullet that struck Donohue severed a major artery, and he nearly bled to death.

Donohue returned to work as a Massachusetts Bay Transportation Authority officer last year.

He announced his retirement Tuesday. Donohue said his injuries make it impossible for him to perform his job at 100 percent.

Media Credit: Drea - 13 Photography Media Credit: Drea - 13 Photography
Media Credit: Drea - 13 Photography