Burgas, Bulgaria (CNN) -- Investigators in Bulgaria are working around the clock to identify the man suspected of killing five Israeli tourists and their bus driver in an airport suicide bombing, the country's interior minister told reporters Friday. Bulgarian Interior Minister Tsvetan Tsvetanov said police were trying to piece together the movements of the suspect, who was carrying a fake Michigan driver's license. Investigators are also working to analyze the bomb, believed to have been located in a backpack placed Wednesday on the bus in a parking lot outside Burgas International Airport, Tsvetanov said. Israel has said it suspects Iran or an Islamist militant group such as Hezbollah is behind the attack, a claim that has added to tension between Israel and Tehran. Iran, which has condemned the attack, has rejected Israel's claims.
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Investigators in Bulgaria are seeking clues to the identity of a suicide bomber
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Minister: "This is a cruel, deliberate and well-orchestrated wave of terror"
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The man was a foreigner who entered Bulgaria with false papers, the interior minister says
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Israel has accused Iran and Hezbollah in the attack, a claim denied by Iran
As Israelis grieved Friday, @placeholder continued the hunt for clues as to who was responsible.