The hit squad that murdered a senior Hamas official in Dubai last month used the stolen identities of six British citizens, and faked at least five other European passports.
Last night, some reports suggested that 17 people were involved in the meticulously planned killing of Mahmoud al-Mabhouh.
Of those whose identities were used, at least three Britons and one German live in Israel. All deny any involvement.
One of the Britons, Melvyn Mildiner, told Reuters: "I am obviously angry, upset and scared - any number of things." The other two have been identified as Paul Keeley and Stephen Hodes.
This latest revelation has fuelled speculation over the involvement of Mossad, the Israeli secret services. The international investigation is expected to examine the role of Israel in the killing.
Officials in Dubai have said that the team appeared to be a professional hit squad. They wore wigs and false beards, paid for everything in cash, and used many mobile phones.
al-Mabhouh was one of the founders of Hamas's military wing, who was wanted by Israel for his part in the kidnapping and killing of two off-duty Israeli soldiers in 1989.