Interior Minister Tsvetan Tsvetanov said the bomb was in the backpack and detonated in the luggage compartment of the bus. The bomber was believed to have been about 36 years old and had been in the country between four to seven days, he said.
Bulgarian prosecutors said the man tried to rent a car in the days before the bombing but was turned down because his ID appeared suspicious. Authorities have examined his fingerprints, his DNA and his fake Michigan driver’s license.
They also said the man actually had short hair. It was not clear if he was wearing a wig, or if he had a haircut after the airport footage was taken.
Afrodita Petrova, the owner of the car rental company, told Bulgarian National TV that the suspect had short dark hair when visiting the office. She said he was the same person from the video camera footage and appeared to be wearing a wig.
“He spoke English with an Arab accent,” she said.
Tsvetanov said the investigation had ruled out that the bomber was a Bulgarian citizen, but did not say how authorities know that. He said the investigation had also ruled out that the bomber was Mehdi Ghezali, a Swedish citizen and former Guantanamo detainee whom authorities had previously fingered as the bomber.
“Now we are focused on finding out the identity of the suicide bomber and his possible whereabouts ahead of the blast,” Tsvetanov said.
Police and prosecutors refused to give any more information, saying it would compromise the ongoing investigation.
The Islamic militant group has not commented on the attack.
Iranian Foreign Ministry spokesman Ramin Mehmanparast called the accusation “baseless.”
A U.S. official told The Associated Press on Thursday night that Hezbollah was believed to be behind the attack. The official spoke on condition of anonymity to discuss a sensitive intelligence issue.
However, Pentagon press secretary George Little said Friday the U.S. government has not established with certainty who was behind the attack.
“The attack does bear some of the hallmarks of Hezbollah, but we are not in a position to make any final determination,” Little said. He declined to say what aspect of the attack resembled the methods or other features of Hezbollah.
Israel has officially issued a complaint with the U.N. Security Council, accusing Iran of responsibility for the attack. Israeli representative Haim Waxman wrote the Security Council president that the attack in Bulgaria was part of an international terrorist campaign against Israelis and Jews worldwide, led by Iran and Hezbollah.