GAZA CITY (AFP) - The Palestinian Islamist movement Hamas on Friday accused Israel of the assassination in Dubai last week of a founder of its military wing while on an arms-buying trip and threatened retaliation. Mahmud Abdel Rauf al-Mabhuh died a martyr in Dubai on Jan 20, 2010 in suspect circumstances, Hamas said in a statement released in its Gaza stronghold. We hold Israel responsible for the assassination of our brother and leader, the statement said, adding Hamas would retaliate for this Zionist crime at the appropriate moment. The Dubai government said police suspect a criminal gang of mostly European passport holders to be behind the killing, but that they had already fled the country. Preliminary investigations indicate that the crime was committed by a professional criminal gang that was following the victim before he came to the United Arab Emirates on January 19, it said. Dubai police will work with the Interpol to capture the suspects, it said in a statement, adding that the culprits left a trace behind that points to them and will help in chasing and arresting them. A brother of Mabhuh charged that Israels Mossad overseas intelligence agency was behind the killing believed to have been conducted by two people. The first results of a joint investigation by Hamas and the UAE show he was killed by an electrical appliance that was held to his head. He was then strangled with pieces of cloth, Fayeq al-Mabhuh, who lives in the Hamas-run Gaza Strip, told AFP. Material was sent to a Paris laboratory which confirmed he was killed by electric shock, he said. He said his brother was in charge of obtaining weapons for Hamas and was in Dubai on a mission for the Islamist movement. The military wing of Hamas, Ezzedine al-Qassam Brigades, said it would soon publish more details of the investigation, adding that the Zionist enemy bears complete responsibility for the assassination. The Hamas official had already been targeted in the past, his brother said, adding that several months ago he was taken in a coma to a hospital in Damascus where doctors later told him he had been poisoned. In Damascus, where Hamas has its leadership in exile, politburo member Izzat al-Rishq also accused Israel of assassinating Mabhuh. The Zionist enemy assassinated commander Mahmud al-Mabhuh in the United Arab Emirates, Rishq said in a statement posted on the groups website, adding that Hamas would avenge the blood shed by the martyr. A funeral was held on Friday in the Yarmuk refugee in the Syrian capital where Mabhuh, 50, had been based for many years. Thousands of mourners attended as Mabhuhs body, wrapped in a Hamas flag, was lowered into a grave at the Palestinian refugee camp of Yarmuk on the outskirts of Damascus. In Dubai, the emirates police chief Lieutenant General Dahi Khalfan said that the slain man had travelled under another name. If we had been told of his presence, we would have provided him with the necessary protection, he told the Al-Arabiya satellite channel. Born in the Jabaliya refugee camp in the north of the Gaza Strip, Mabhuh was one of the founders of the Ezzedine al-Qassam Brigades. Hamas said Mabhuh was behind the capture of two Israeli soldiers in separate operations in 1989 during the early stages of a 1987-1993 Palestinian uprising. Soldiers Avi Sasportas and Ilan Sadon were both later killed. Mabhuh also masterminded a number of other attacks on Israeli targets and Israeli authorities demolished his home in Gaza in retaliation. Mabhuh spent several spells in Israeli custody. After his last release, he spent his life being hounded by the Zionist occupier until he succeeded in leaving the Gaza Strip, Hamas said. Over the years, a number of Hamas leaders have died in operations Israel calls targeted killings.