Hatem al-Aribi told The Associated Press that the bodies were found near the eastern city of Bayda the temporary home of Libya's internationally-recognized government.
The capital, Tripoli, was overrun last year by militias allied with Islamist factions who then set up their own government and revived the previous parliament.
The elected parliament now meets in the eastern city of Tobruk and the executive branch operates from nearby Bayda.
Al-Aribi says that the five, from the Barqa TV network, were abducted in August while travelling to their hometown of Ajdabiya after covering the opening of the parliament in Tobruk.
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Libya has collapsed into dueling governments backed by rival militias.
Since August last year, hundreds of thousands have been displaced, diplomatic missions have abandoned the capital and several cities have been heavily damaged.
Amid the chaos, the extremist Islamic State group has established a strong presence in the cities of Darna and Sirte.
The group has captured and beheaded dozens of Christian laborers and migrants in recent months.