TEGUCIGALPA, Honduras — A Honduran tribunal has convicted four police officers in the 2011 killing of the son of the president of Honduras National Autonomous University and his friend, a case that set off a campaign to clean up the Central American nation's corruption-plagued national force.

The tribunal found two of the officers guilty of firing the shots that killed university president Julieta Castellanos' 22-year-old son and a 23-year-old friend. The other officers were found guilty of masterminding the slayings. All face up to 40 years in prison.

The young men were last seen after being stopped at a police checkpoint outside Tegucigalpa. Their bodies were found the next day.

Castellanos has led a crusade since then to overhaul the National Police and fire officers involved in drug trafficking, murder and kidnapping.