JAKARTA, Indonesia -- The alleged operations chief of Southeast Asian terror group Jemaah Islamiyah fled to Pakistan and may have been replaced by the brother of the prime suspect in the Bali bombings, Indonesia's national police chief said Wednesday.

The revelation, echoed by the country's intelligence chief, appeared to bolster allegations that the al-Qaida-linked group was behind the Oct. 12 blast that killed more than 190 people and injured hundreds more.

The chief suspect in the blast, a former motorcycle mechanic identified only as Amrozi, appeared in Bali on Wednesday in a bizarre, 40-minute interview with national police chief Gen. Da'i Bachtiar.

Laughing and waving to reporters invited to watch, Amrozi told Bachtiar he was "delighted that it (the bomb) successfully exploded."

Bachtiar told reporters it was "very possible" that the suspect's older brother, Mukhlas, is serving as Jemaah Islamiyah's new operations chief, having taken over from Riduan Isamuddin, also known as Hambali.

Several security experts have said Hambali -- the most-wanted man in Southeast Asia -- probably organized the Bali nightclub bombings, the most deadly terrorist act since the Sept. 11 attacks in the United States.

Accounts from several witnesses indicated "Hambali left Malaysia for Pakistan after the Sept. 11 attack to hide away," Bachtiar said. Investigators spoke to witnesses in Indonesia, Malaysia and Singapore, he said.

He added that police had "received confirmation that Mukhlas was an important figure" in Jemaah Islamiyah and that it was "very possible" he'd taken over Hambali's role.

The state-run Antara news agency also quoted Indonesian intelligence chief Hendropriyono as saying that Mukhlas was Hambali's replacement. Like many Indonesians, Hendropriyono uses one name.

According to authorities, Amrozi confessed to being a field commander for Jemaah Islamiyah, which reportedly seeks a massive Islamic state across Southeast Asia.