As officials tried to identify attacker, Hezbollah and Iran were blamed.
BURGAS, BULGARIA - He looked like any other impatient tourist checking the big board at airport arrivals: a lanky, long-haired man in a baseball cap with his hands in the pockets of his plaid Bermuda shorts, a bulky backpack hanging from his shoulders.
Minutes later, authorities say, the man, filmed by security cameras at the Burgas airport, would board a bus filled with Israeli tourists and blow himself up, killing six others as well.
Authorities looked Thursday for clues as to who he was, using his fingerprints, his DNA and his fake Michigan driver's license.
Despite the uncertainty, Israel was quick to blame Iran and its Lebanese ally Hezbollah for the attack Wednesday.
Israeli Prime Minister Benjamin Netanyahu said the bombing "was carried out by Hezbollah, the long arm of Iran." Israel has attributed a series of attacks on its citizens around the world in recent months to Iran and Hezbollah.
Unnamed U.S. officials, cited by the New York Times, also said that Hezbollah was behind the attack and that the bomber had been "acting under broad guidance" to hit Israeli targets when opportunities presented themselves.
The bombing, a senior U.S. official told the Times, was in retaliation for the assassinations of Iranian nuclear scientists, which Iran has blamed on Israeli agents -- an accusation that Israel has neither confirmed nor denied.
Iranian Foreign Ministry spokesman Ramin Mehmanparast called the accusation of Iranian involvement "baseless."
The victims in Burgas included the Bulgarian bus driver and five Israelis, one a pregnant woman.
The attack occurred shortly after the Israelis boarded a bus outside the airport in the Black Sea resort town of Burgas, a popular destination for Israeli tourists -- particularly for high school graduates before they are drafted into military service.
On Thursday, Bulgarian television aired security camera footage showing the suspected bomber wandering in and out of the terminal shortly before the blast. He was dressed as a tourist himself, wearing a baseball cap, T-shirt, plaid shorts and sneakers with short white socks. He carried a large backpack with wheels.
Bomb in backpack
Interior Minister Tsvetan Tsvetanov said the backpack contained the bomb. The bomber was believed to have been in his 30s and had been in the country between four and seven days, Tsvetanov said without elaborating.
"We cannot exclude the possibility that he had logistical support on Bulgarian territory," the minister said.
Officials were using DNA samples to try to establish his identity. Bulgarian Prime Minister Boiko Borisov told reporters that a Michigan driver's license was retrieved, but U.S. officials said there was "no such person in their database." Bulgarian television aired footage of the license showing the name of Jacque Felipe Martin with an address in Baton Rouge, La.
Michigan officials said they told the FBI that no one by that name had a valid Michigan license and that out-of-state residents cannot be issued one anyway.
Some Bulgarian news reports identified the bomber as 33-year-old Stockholm-born Mehdi Ghezali, reportedly released from U.S. confinement at Guantanamo Bay in 2004 and sent back to Sweden.
But Sweden's security services on Thursday flatly denied that the man was involved. "We can confirm that it was not Mehdi Ghezali," said Mark Vadasz, head of communications for the Swedish security services.
The Israeli tourists had just arrived on a charter flight from Tel Aviv carrying 154 people, including eight children. Some of them told Israeli television that they were just boarding the white bus in the airport parking lot for a ride to their hotel when the blast occurred.
On Thursday, Bulgarian authorities dispatched 200 police to hotels where about 1,000 Israelis were staying just north of Burgas. A representative of the Ortanna tour company, which books tours from Israel, said about 10,000 Israelis had scheduled vacations in Bulgaria through the firm this summer and about half had canceled after the attack.
Flown home to Israel
A military plane carrying 33 Israelis injured in the bombing arrived Thursday in Israel. At least two critically injured Israelis were sent to Sofia, the Bulgarian capital, for treatment, according to the head of the Israeli military medical corps, Brig. Gen. Itzik Kreis.
A Bulgarian government plane was to fly home 100 other Israelis who were not wounded, but who wanted to cut short their vacation.
The Bulgarians are still trying to figure out how the bomber entered the country, how he traveled around the country and where he stayed.
"We're not pointing the finger in any direction until we know what happened and complete our investigation," said Nickolay Mladenov, Bulgaria's foreign minister, in an interview.
He was speaking in front of the airport, where three giant flags, one for Bulgaria, one for Burgas and one for the European Union, flew at half-staff.
The New York Times and McClatchy News Service contributed to this report.