Revolutionary fighters caught Seif al-Islam Gadhafi Saturday in southern Libya. He is accused of committing crimes against humanity.
Al-Islam's capture comes less than a month after his father was found and killed.
In addition to al-Islam, Libyan Information Minister Mahmoud Shammam said ex-intelligence minister Abdullah al-Senoussi was captured alive on Sunday not far from where Gadhafi's son was seized on Saturday while trying to flee to neighboring Niger.
Shammam said al-Islam, the ousted Libyan leader's one-time heir apparent, must be tried in Libya, even though the country's new leaders have yet to establish a court system.
The Associated Press contributed to this report.