Gunmen shot dead Libyan army general and high-ranking defence ministry official Mohamed Hadia on Friday in the eastern city of Benghazi, one of his sons said.
"My father was returning from the mosque after Friday prayers with a neighbour when a car stopped in front of them with four people on board," Ahmad Hadia told AFP.
"They asked for his identity, then shot him dead," he added.
The motive for the murder was not immediately clear and the identity of the gunmen unknown.
Hadia was one of the first officers to defect and join the opposition during last year's revolution that ousted Muammar Gaddafi.
After the revolution he was appointed head of armaments at the defence ministry.
Hadia is the latest of dozens of security officials murdered in Benghazi, especially of officers who had served under Gaddafi.