SOFIA, Bulgaria — A sophisticated group of conspirators was involved in the suicide bombing that killed five Israeli tourists and a Bulgarian bus driver last week, and they spent at least a month in Bulgaria before the attack, the country’s prime minister said Tuesday.
Boiko Borisov’s comments confirm suspicions that the suicide attacker who targeted a bus filled with Israeli vacationers last Wednesday did not act alone.
However, the prime minister did not offer any evidence or give many more details. He did not say how many people were thought to have been involved in the attack in Burgas, and he also declined to back up Israel’s claims that Iran and the terrorist group Hezbollah played roles.
The conspirators used “leased vehicles. They moved in different cities so as not to be seen together, and no two of them can be seen in one place on any security camera,” Mr. Borisov said, speaking alongside visiting White House counterterrorism chief John Brennan.
Mr. Borisov described the people behind the blast as “exceptionally skilled” and said they operated under “strict conspiracy rules.” He also said DNA samples from the suicide bomber have been shared with all allied security services, but no match has been found.
“There was absolutely no chance of preventing such an act of violence,” Mr. Borisov insisted. “We could have only detected it by chance or if we had been informed by the services that such activities were under way in Bulgaria.”
Mr. Brennan also stopped short of blaming Iran or Hezbollah, though he noted both Tehran and the Lebanese group had been implicated in attacks on civilians in the past. He said the United States has been working with Bulgaria as the country tracks down those responsible.
Investigators know that the suicide bomber was using multiple aliases and was wearing a wig and disguise when he was captured on closed circuit television, according to a European security official who spoke on condition of anonymity because he was not authorized to speak about the investigation..