Indonesian investigators say they are carefully studying an amateur video showing a man with a backpack they believe was filled with explosives. The footage shows him casually walking through a Balinese seaside restaurant packed with people just moments before one of Saturday's bombs exploded.
National police spokesman Sunarko says police believe the man in the video is one of three suicide bombers.
Police say the bombers used the same tactics to set off near simultaneous blasts in three restaurants in two popular spots on the island that were packed with locals and foreign tourists.
They say the bombers strapped explosives to their bodies, which were packed with ball bearings to make them more deadly. They say the blasts blew apart the bombers' torsos, but left their heads relatively unscathed.
Pictures of the three severed heads are being circulated nationally, in newspapers and on television, in hopes of identifying the men.
Police spokesman Sunarko says the authorities hope someone will recognize the severed heads and come forward to help police identify the bombers.
Investigators say the attacks bear the hallmark of the regional terrorist group Jemaah Islamiyah, which is also blamed for the 2002 bombings in Bali that claimed 202 lives, many of them foreign tourists. Saturday's bombings killed about 22 people including the three bombers, and injured more than 100.
Jemaah Islamiyah is also believed responsible for the 2003 bombing of the J.W. Marriott Hotel in Jakarta that killed 12 people, and the 2004 bombing outside the Australian embassy in Jakarta that claimed 10 lives.
Indonesia has the world's largest Muslim population, but the Balinese are primarily Hindus. On Monday, Hindu leaders held prayer ceremonies to cleanse the bomb sites, while local people laid wreathes of flowers for the dead.
Some foreign tourists left the island after the bombing, but many have decided to remain. Beaches, hotels, and shops are still filled with holiday-makers.
But the attacks have many Balinese worried. Around 80 percent of the people rely on the tourism industry to make a living, and the island's economy was just recovering from the 2002 bombings when Saturday's attack occurred.
Yanti Sukamdani, chairwoman of the Indonesian Hotel and Restaurant Association, says while it is still too early to know what affect the bombings will have on Bali's crucial tourism industry, the hotels remain full. "We have investigated hotels, especially in the Kuta area, of course there is some effects, but very, very limited effects," he said.
Americans, Japanese, Australians, and Koreans are among those who were injured in the bombings, but many locals were among the casualties.