Investigators lifted fingerprints, swabbed dust and collected tissue from the wreckage of three car bombings Saturday and detained dozens of Bedouin tribesmen, including quarry workers who could have provided the explosives that killed at least 34 people.

Israel blamed Al Qaeda for the Thursday night attacks in two Sinai resorts, and Egyptian investigators were leaning toward an Al Qaeda connection as well.

Egyptian investigators said they suspected eight to 10 terrorists targeting Israeli tourists carried out the attacks, possibly slipping in from Saudi Arabia or Jordan on speed boats.

They also said there was a chance a local sleeper cell of Egyptians might have been activated to stage the attacks, Egypt's first terrorist strike in seven years.

Speaking on condition of anonymity, the investigators said such a group would almost certainly be linked to Ayman al-Zawahri (search), who led the extremist Egyptian Islamic Jihad (search) before merging the group with Al Qaeda in 1998.

The Egypt-born Zawahri is Usama bin Laden's top deputy.

One of the car bombs exploded at the Taba Hilton (search) just south of the Egypt-Israel border and two blew up in Ras Shitan (search), a town of beach bungalows 35 miles to the south on the Red Sea coast.

At the Hilton, where the blast sheared 10 stories off one wing, rescuers removed large slabs of concrete covering the lobby and dug down into the basement shopping concourse. The Israeli military said three bodies, including a toddler, were pulled out Saturday. Rescue official Mark Zev said one body found in the basement was of a guest who had been on the hotel's sixth floor.

Egyptian officials said 34 people were known dead, including nine identified as Egyptians and five as Israelis. Israeli authorities, who reported 33 dead, broadcast calls for relatives of the missing to donate blood for DNA comparisons with unidentified bodies.

Vladimir Bondarenko at the Russian Embassy in Cairo said at least one Russian woman was killed and 11 Russians were unaccounted for. Two Italian sisters also were missing.

Investigators — both Israeli and Egyptian — scoured the bomb sites, photographing the craters and using lasers to measure blast distances.

They lifted fingerprints from the remains of a car at the Taba Hilton that was believed to have held 440 pounds of explosives and took DNA samples from nearby body parts in an effort to determine who the suicide bombers were, Egyptian security officials said, speaking on condition of anonymity.

Investigators also were doing "dust analysis" around the blast sites to determine the type of explosives used, said one official who also worked on the 1997 massacre of 58 foreign tourists in Luxor, Egypt's last terrorist attack.

A team of four Egyptian prosecutors visited Ras Shitan, followed minutes later by five Israeli investigators who emerged from a minivan. U.S. diplomats also visited the camps, and one investigator said they were checking on any American casualties.

Several flattened bungalows were visible at the Moon Island Village camp, but police kept journalists away. The other camp, known as Castle Rock, was also closed.

Police detained dozens of Bedouin tribesmen on suspicion of providing explosives for the attacks, security officials said on condition of anonymity.

A senior police official, also speaking on condition of anonymity, said 20 people were being held, some of them quarry workers who presumably had access to explosives. Israel's Channel 2 television said 30 Bedouins were detained, two of whom it said were "more serious suspects."

Two Egyptian security officials, speaking on condition of anonymity, said investigators felt the attacks were conducted by eight to 10 men, some of whom were suicide bombers.

They said at least one woman saw two men in the car believed used in the Taba attack before it exploded and was able to provide detailed descriptions.

"It was dark and she could not give 100 percent details, but the information she gave is good and provided some clues about how it all happened," one official said.

The officials said investigators were focusing on two possible scenarios, one involving foreign terrorists who slipped in from Jordan or Saudi Arabia on speed boats and another involving a sleeper cell in Egypt that was awakened for the attacks.

"It seemed to be planned and designed like the September 11th attacks so that the explosions would take place simultaneously," one of the officials said.

He said investigators were leaning toward the foreigners scenario because of the sophistication of the coordinated attacks, saying the sleeper cell was considered only a 10 percent to 15 percent possibility.

Israeli officials said they believed Al Qaeda was behind the attack.

"The type, the planning, the scope, the simultaneous attacks in a number of places, all this points to Al Qaeda," Israeli Foreign Minister Silvan Shalon told Channel 2.

U.S. officials also said Al Qaeda likely played a role.

Abdel Rahim Ali, an Egyptian expert on Islamic radical groups, said whether the attackers came from Egypt or another country, Al Qaeda's involvement was clear.

"Egyptian extremist groups can hardly execute such big operations," he said. "They lack expertise and potential."

Israel's government, which last month warned citizens not to travel to the Sinai, said that its warnings remained in effect and that all Israelis should return home.

Thursday's attacks "don't lessen, even in the slightest, the risk that this will happen again," counterterrorism chief Dan Arditi told Israel radio.