The two living suspects in a bus attack that killed five Israeli tourists in Bulgaria last year have been identified and both are now living in Lebanon, a top Bulgarian security official said Wednesday.

The bomb that exploded July 18 as the Israeli tourists were boarding a bus at the airport in Burgas also killed a Bulgarian bus driver and the suspected bomber. Three men are suspected in the attack, including the dead bomber.

On Tuesday, an official Bulgarian report said investigators had "well-grounded reasons to suggest" that two of the suspects belonged to the militant wing of the Islamist group Hezbollah. The report said they had been living in Lebanon for years, one with a Canadian passport and the other with an Australian one.

Stanimir Florov, head of Bulgaria's anti-terror unit, said Wednesday that the names of the suspects were known, they were now based in the same country and "we have asked Lebanese authorities to assist in our investigation." He did not elaborate.

Vancouver with his mother

The identity of the bomber remains unknown even though his DNA samples have been shared with intelligence agencies in other nations, he said, adding that no DNA match has been found in their databases.

Florov said the bomb was likely supposed to explode while the bus was in motion "but the terrorists obviously made a mistake."

Europol director Rob Wainwright confirmed that comment, telling The Associated Press that investigators believe the bomber never intended to die. A Europol expert who analyzed a fragment of a circuit board from the bomb determined that it was detonated remotely, he said.

'As far as we know, he has not normally been a resident of Canada since he left 10 years ago.'—Immigration Minister Jason Kenney

If the explosives had blown up while the bus was full, there would have been many more victims and much of the evidence would have been destroyed, Florov said.

"In that case, the investigation would have started from ground zero," he said.

Canadian Immigration Minister Jason Kenney said one of the suspects was born in Lebanon, came to Canada as a child, became a Canadian citizen, and then left at age 12. He said he assumed the man was a dual Lebanese-Canadian citizen.

“This individual came to Canada as a child — I think at the age eight — settled into Vancouver with his mother, and became a citizen three, four years later," Kenney told the CBC's Evan Solomon in an interview on Power & Politics.

“We think it’s possible he may have come back since then … a couple of times, visiting Canada, but we don’t have records on when that might have been,” he said. "As far as we know, he has not normally been a resident of Canada since he left 10 years ago."

With files from CBC News