The ambulance did not break down due to a faulty emissions prevention system, as previously thought.
A preliminary inquiry says a D.C. ambulance that shut down while taking a gunshot victim to the hospital had a mechanical problem caused by a clogged fuel filter screen.
The problem occurred last month after Nathaniel McRae, who was shot by police officers after a carjacking, had to be transferred to another ambulance after the one he was in broke down.
McRae later died, though fire officials say the delay of up to seven minutes did not contribute to his death.
Fire officials initially blamed the breakdown on emission system safeguards mandated by the Environmental Protection Agency. But a preliminary review cites a clogged fuel filter screen, which can cause an engine to shut down.
The manufacturer has agreed to remove the screens from the vehicles that have them.