Libya's military police chief, Colonel Mustapha al-Barghathi, was shot dead Friday in the restive eastern city of Benghazi, the security services said.
Unknown assailants gunned down Barghathi outside his home, Colonel Abdullah al-Zaidi, spokesman for the security services, told AFP.
He said Barghathi -- a former rebel leader in the 2011 uprising that toppled longtime dictator Muammar Gaddafi -- died of head and chest wounds at the Mediterranean city's Al-Jala hospital.
Barghathi was the first officer in Gaddafi's army to defect and form a rebel force in the revolt, Zaidi said.
Benghazi was the cradle of the uprising that toppled Gaddafi's regime, but has since seen a series of assassinations targeting officers in the security services.
Other attacks have targeted Western interests and diplomats, and much of the violence, including the killing of US ambassador Chris Stevens and three other Americans in an attack on the US mission last year, has been attributed to radical Islamists.
The attacks have not been claimed and no arrests have apparently been made.
Two years after the revolution, Libya's new authorities have failed to establish a new army and police force, and are still struggling to rein in tribal militias and groups of former rebels.