Hamas last night vigorously denied that a renegade from its own ranks helped set up the assassination of Hamas leader Mahmoud al-Mabhouh in a Dubai hotel room last month, a shock claim made by Dubai's police chief, as echoes from the killing and its investigation continued to resound in the Middle East and Europe.

Gulf News and al-Khaleej newspapers in the United Arab Emirates yesterday quoted the police chief, Lieutenant-General Dahi Khalfan Tamim, as saying that a Hamas member played a significant role in the killing of Mahmoud al-Mabhouh. The Dubai police believe the primary perpetrators came from Israel's Mossad agency. General Tamim said the Hamas member leaked information on Mr Mabhouh's whereabous to the suspected assassins.

In Brussels, a meeting is planned today in which the Foreign Minister, David Miliband, is expected to seek answers from his Israeli counterpart, Avigdor Lieberman, on Israel's alleged theft of the identities of six UK nationals to use their names in false passports used by the alleged hit squad to commit the assassination on 19 January. And the Irish Foreign Minister, Micheal Marin, will also be seeking explanations from Mr Lieberman on the use of faked Irish passports.
But it seems doubtful that Mr Lieberman will tell them anything of substance during the encounters on the sidelines of a scheduled meeting of EU foreign ministers because Israel is adhering to its refusal to acknowledge responsibility in the assassination.

The number of fake Irish passports involved was originally thought to be three but is now five. Dubai police say a total of 19 people participated in the killing, of whom it has identified 11.

The claim that there was a Hamas collaborator adds further intrigue to the killing, already seen as having a spy-novel ambience. The assertion came in response to a request by the Gaza-based Hamas leader, Mahmoud Zahar, that the UAE extradite to Gaza two Palestinian suspects the Dubai police are holding in connection with the assassination. The police chief said: "I asked him to initiate an internal investigation because I am certain that there has been a security breach from their side."

If a renegade within Hamas did help the Israelis, it would be a major setback to the group's prestige and, in an immediate sense, would be cause for its leaders to be even more wary of their own surroundings. A statement released by Hamas headquarters in Damascus rejected the possibility that a member was involved in the assassination. It said that Mossad's success in tracking Mr Mabhouh "doesn't mean that there exists a [security] breach". A member of the Damascus-based politburo, Sami Khater, said on Hamas's Palestinian Information Centre website, "We've said from the beginning that the Mossad agency is responsible, and if the Mossad succeeded in enlisting some followers, whether Palestinians or from other nationalities, that doesn't change the reality at all. The perpetration, planning and implementation is solely the responsibility of the Mossad".

Hamas is irate that the UAE has refused to allow any of its personnel to participate in the investigation. But its rival, the Fatah movement, keeps commending the Dubai police's investigatory work. Fatah had also made similar suggestions about a Hamas insider being involved in the planning for the assassination.

Further weekend reports pointed towards another Israeli connection. Apparently, the British passports had all been taken briefly during routine Israeli airport checks andcopied, and a separate report speculated that the Israeli Prime Minister, Benjamin Netanyahu, had personally authorised the assassination.

A Fatah MP, Abdallah Abdallah, called for tough action by Britain and other European countries over the passport fraud, recalling that after a crisis 23 years ago over Mossad passport use, Israel had promised not to misuse British passports again. "These crimes should not be tolerated," he said. "Otherwise, the impression will be that the countries that tolerate them are accomplices."

But Danny Ayalon, the Israeli Deputy Foreign Minister, appeared to dismiss the passports issue "because there is nothing that ties Israel to the assassination. Britain, France and Germany all share our interests in the fight against global terror, therefore there will be no crisis".

One week on: The twists in the tale

*Monday, 15 February: Dubai police announce that Hamas official Mahmoud al-Mabhouh – found dead in a hotel room on 19 January – had been killed by an 11-strong hit squad who travelled on European passports.

*Wednesday, 17 February: Israel's Foreign Minister Avigdor Lieberman says there "is no reason to think it was the Israeli Mossad" behind the crime, but stops short of a denial. Gordon Brown demands an inquiry into the use of British passports.

*Thursday, 18 February: In an interview with 'The National' newspaper, Dubai's police chief, Lt-Gen Tamim, says it is "99 per cent, if not 100 per cent" certain, that Mossad was behind the murder.

*Friday, 19 February: The British Foreign Office denies it received a tip-off before the killing. David Miliband calls the crime an "outrage".

*Sunday, 21 February: Lt-Gen Tamim suggests that a Hamas source leaked travel plans to Mr Mabhouh's killer.