Mussa Ibrahim, who served as the last spokesman for deposed Libyan leader Muammar Qaddafi, was arrested on Saturday southwest of the capital, the prime minister’s office said.
“Moussa Ibrahim has been arrested by forces belonging to the Libyan government in the town of Tarhouna and he is being transferred to Tripoli to begin interrogation,” a statement from the prime minister’s office said.
Tarhouna is 70 km (40 miles) south of the capital, Tripoli.
Fluent in English, Ibrahim would hold regular press conferences in the luxury Tripoli hotel were journalists stayed during last year’s war.
His whereabouts have been unknown since the fall of Tripoli in August 2011 but there have been past reports of his capture.
Saturday marks one year since Qaddafi’s capture and death in his hometown Sirte, after he was caught hiding in a drain pipe.