WASHINGTON, July 23 (UPI) -- Bulgarian authorities are focusing an investigation into last week's suicide bombing on Sweden given its high number of Hezbollah chapters, a source said.
At least seven tourists, including Israeli citizens, were killed Wednesday in a suicide attack on a tour bus in Burgas, Bulgaria. The Israeli government accused Iran and Shiite movement Hezbollah of carrying out the attack, allegedly conducted by a man carrying a false U.S. identification card.
Israeli Prime Minister Binyamin Netanyahu said, during the weekend broadcast of CBS's "Face the Nation," that he had "unquestionable" evidence to suggest the attack was the work of Iran and Hezbollah.
The Wall Street Journal, citing a person familiar with the investigation, said authorities weren't able to match the bomber's fingerprints with potential suspects. Investigators are working with Swedish forensic teams as Hezbollah has a strong presence in the country, the newspaper reported.
Bulgarian authorities said they are searching for an alleged accomplice.
Iran and Hezbollah denied links to the attack. U.S. officials, the Journal reported, said the attack is similar to previous operations planned by Iran and the Shiite resistance movement, however.