MISRATA, Libya (AP) -- Longtime Libyan dictator Moammar Gadhafi, his son Muatassim and a top aide were buried in an Islamic ceremony at dawn Tuesday in a secret location, with a few relatives and officials in attendance, officials said.

The burial closed the book on Gadhafi's nearly 42-year rule and the 8-month civil war to oust him, but did not silence international calls for an investigation into whether the widely despised tyrant was executed by his captors.

Meanwhile, a government spokesman said an explosion rocked a fuel depot near Gadhafi's hometown of Sirte on Monday and that there were casualties. Col. Ahmed Bani said the blast is being treated as an accident, but that an investigation has been launched.

A human rights researcher, Tirana Hassan, said that while in Sirte on Monday, said she saw 11 people with severe burns arrive at the city's Ibn Sina hospital. Nurses said the injuries were from the blast.

The bodies of Gadhafi, Muatassim and former Defense Minster Abu Bakr Younis were removed overnight from the commercial freezer in Misrata where they'd been on display for four days. They were then buried at dawn Tuesday, according to Ibrahim Beitalmal, a spokesman for the military council in Misrata. Bani also confirmed the burial.

In a text message, Beitalmal said Islamic prayers were read over the bodies and that relatives and members of the local and military councils of Misrata attended the funeral. Beitalmal could not immediately reached by phone Tuesday to provide further details.

On Monday, Beitalmal said the three would be buried in unmarked graves to prevent vandalism. Presumably, the location would also be kept hidden to prevent it from turning into a shrine for Gadhafi loyalists.

International organizations asking to see the burial site would be given access, Beitalmal said.

The three bodies had been held in cold storage in Misrata since the dictator and members of his entourage were captured near his hometown of Sirte on Thursday after their convoy came under attack by NATO. For days, Misratans had lined up to see the bodies, donning surgical masks to cover the stench from the bodies.

Over the weekend, Libya's chief pathologist, Dr. Othman el-Zentani, performed autopsies on the three bodies and also took DNA samples to confirm their identities. El-Zentani has said Gadhafi died from a shot to the head, and said the full report would be released later this week, after he presents his findings to the attorney general.

Gadhafi and Muatassim were captured alive, with some injuries, but died in unclear circumstances later that day.

Responding to mounting international pressure, Libya's interim leaders have promised an investigation to establish whether Gadhafi was killed in an execution-style slaying after being captured alive Thursday by fighters in his hometown of Sirte or whether he died in the crossfire as government officials have suggested. Video footage showed him being beaten and abused by a mob after his capture.

The New York-based Human Rights Watch said there are strong indications that Gadhafi was killed in custody.

Hassan, a researcher for the group, said she spoke Monday to a 30-year-old Sirte resident who had traveled in the convoy that tried to smuggle Gadhafi out of Sirte.

Hassan quoted the woman as saying that Gadhafi did not sustain serious injuries during the NATO strike on the convoy.

The woman said the former Libyan leader and members of his entourage left their vehicle after the attack and took cover for about three hours in an abandoned building. Gadhafi then left the hideout with a small group on foot, and they were captured a short while later, Hassan quoted the woman as saying.

The woman, who had volunteered at a field clinic in Sirte treating wounded Gadhafi loyalists, was released by the revolutionary forces and has returned to Sirte, Hassan said.