A preliminary investigation conducted by Hamas suggests that the assassination of one of its officials in Dubai last month was likely carried out by agents of an Arab government, and not by Israel's Mossad spy agency.

When Mahmoud al-Mabhouh, a senior Hamas official reportedly behind the smuggling of Iranian arms to Gaza, was found dead in his hotel room on January 20, the organization was quick to point the finger at Israeli intelligence, vowing revenge attacks.

But details of a Hamas inquiry passed to Haaretz reveal that Arab states, not Israel, now top the suspect list.

Both Hamas and Dubai police say that Mabhouh had enemies across the Middle East, any of whom may have had a motive for his murder.

A Hamas source told Haaretz on Monday that Mabhouh was wanted by authorities in both Jordan and Egypt, where he previously spent a year in prison.

Hamas also suspects its Palestinian rivals in the West Bank.

"It is quite possible that Palestinian Authority security forces were involved," Osama Hamdan, a Hamas leader in Lebanon, told Hezbollah's television station Al-Manar on Monday.

"West Bank forces are persecuting our fighters and have killed dozens since 1994," he said.

Meanwhile, the Saudi daily Okaz reported on Tuesday that Hamas has decided to halt temporarily negotiations over the release of abducted Israel Defense Forces soldier Gilad Shalit due to Mabhouh's murder.

A senior Hamas official told the paper that the prisoner swap talks have reached a critical juncture and reiterated the group's stance that Israel is responsible for the delay in its completion.

Details of Mabhouh murder begin to emerge

On Sunday, a Dubai police commander updated the Palestinian consul in the United Arab Emirates on progress in the investigation. Mabhouh was killed by a seven-man team, four whom had been identified, the commander said.

According to Hamas investigators, Mabhouh arrived in the Syrian capital Damascus at 9:00 A.M. on the morning of January 19, where he boarded flight EK912 for the UAE, landing at Dubai at 2:30 P.M.

Local authorities were unaware of the presence of the Hamas leader, who traveled under a false identity. Al-Mabhouh took a taxi to the luxury Al Bustan Rutana Hotel, where he checked into room 130, also under a false name.

As always when traveling, al-Mabhouh had taken the precaution of reserving in advance a room with no balcony and sealed windows. On arrival, he deposited a case of documents in the hotel safe before spending around an hour in his room.

Between 4:30 P.M. and 5:00 P.M. al-Mabhouh left the hotel for a meeting. Hamas claims to know the identity of his Dubai contact - but has so far kept details under wraps.

Hamas assumes that he dined outside the hotel, which has no record of him ordering food or drink, before returning to his room at around 9:00 P.M.

Police say it is likely that Mabhouh answered the door to his assailants - but Hamas believes the attackers awaited him on his return and were warned of his approach by accomplices tailing him.

At 9:30 P.M. Mabhouh's wife called his cellular telephone. There was no answer. Both Hamas and police believe the victim was by then already dead. His body was discovered the following day.

Post mortem examinations revealed signs of electrocution beneath both ears -presumably from a device used to stun Mabhouh, whose nose was bleeding and whose teeth showed signs of abrasion.

Pathologists determined the cause of death as asphyxiation, probably with a pillow found near the body and stained with blood.

Meanwhile, London's Sunday Times reported on Sunday that Mabhouh had been injected with a drug that simulated the effects of a natural heart attack.

Also on Sunday, Israeli Infrastructure Minister Uzi landau denied that Mossad agents had posed as part of his entourage to carry out the hit. Landau, the first Israeli minister to travel officially to the UAE, left the country three days before Mabhouh was killed.

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