Mussa Ibrahim said Saif al-Arab was a civilian and a student who had studied in Germany. He was 29 years old.
Libyan officials took journalists to the house, which had been hit by at least three missiles. The roof had completely caved in in some areas, leaving strings of reinforcing steel hanging down among chunks of concrete.
A table football machine stood outside in the garden of the house, which was in a wealthy residential area of Tripoli.
(Reporting by Lin Noueihed; Editing by Matthew Jones)