Tripoli, Libya (CNN) -- Libyan revolutionary forces have captured the country's former intelligence chief, National Transitional Council officials said Sunday.
Abdullah al-Senussi -- Moammar Gadhafi's brother-in-law -- was captured at his brother's house about 100 kilometers north of Sabha, senior National Transitional Council member Mohammed Sayeh said.
Al-Senussi was in custody in Sabha Sunday, Sayeh said, and authorities planned to bring him to Tripoli to stand trial.
He was not harmed during his capture, said Abdel Hafiz Ghoga, deputy chairman of Libya's National Transitional Council.
Earlier this year the International Criminal Court in the Netherlands indicted al-Senussi for crimes against humanity after the uprising against Gadhafi's regime began in February.
The court prosecutor's arrest warrant said al-Senussi "exercised his role as the national head of the Military Intelligence, one of the most powerful and efficient organs of repression of Gadhafi's regime."
The announcement of his arrest came a day after the NTC said forces had captured Gadhafi's son Saif al-Islam Gadhafi -- who was also indicted by the ICC on charges of crimes against humanity.
On Saturday, Libyans celebrated the reported capture of Gadhafi's son, nabbed in a desert gun battle after an 18-day stakeout.
Senior Libyan military officials said they believe the potential Gadhafi successor was trying to make his way to neighboring Niger, where a brother, Saadi, was granted asylum.
On Saturday ICC spokesman Fadi el-Abdallah told CNN that Libya has an obligation to surrender Saif al-Islam to the ICC. If Libya wants to conduct a trial, it needs to submit a request to judges and show its legal system is capable of properly handling such a proceeding.
Officials in Libya have said they want to put Saif al-Islam on trial.
ICC Chief Prosecutor Luis Moreno-Ocampo was scheduled to arrive in Libya Sunday to check on Saif al-Islam's condition, Ghoga said.
Due to security concerns, the NTC official said Saif al-Islam would remain in custody in the western city of Zintan until authorities make arrangements for his trial.
Video released by the Zintan Media Center this weekend showed a heavily bearded Saif al-Islam saying he is "getting proper medical treatment."
"I'm here with my brothers and we're talking. This is my situation here in Zintan," he says.
An investigative committee has been set up to handle Saif al-Islam's case, Ghoga said.
Meanwhile, plans to announce the nation's transitional government were delayed after the country's acting prime minister requested more time to pick his proposed Cabinet, Ghoga said.
Acting Prime Minister Abdurrahim El-Keib will submit names for the new government to the NTC for approval within 48 hours, Ghoga said.