Forensic tests proved that the murdered Hamas commander Mahmoud al-Mabhouh was suffocated to death, Dubai police said Sunday.

The cause of al-Mabhouh's death was suffocation using a pillow, Major General Khamis Mattar Al Mazeina, deputy director of Dubai police, was quoted as saying by Dubai-based English daily Gulf News on its website.

One more suspect will be added to the list of suspects in the assassination, bringing the total identified suspects to 27, Al Mazeina said.

According to the website of Arabian Business, a Dubai-based business journal, forensic tests also showed that there were "substantial" quantities of succinylcholine in al-Mabhouh's body.

The drug, used to induce anaesthesia, is also a muscle relaxant that could "cause immediate and temporary paralysis," a police spokesman was quoted as saying.

He said that while the drug was usually difficult to trace, in this instance it had been administered in quantities which made it easy to detect.

Al-Mabhouh, a senior commander of Hamas military wing the Ezzedeen al-Qassam Brigades, was born in the Gaza Strip but has been living in Syria since 1989. He was found dead in his hotel room on Jan. 20, a day after he arrived in Dubai.

The Hamas official was wanted by the Israeli government in connection with the kidnappings of two Israeli soldiers in 1989. Dubai police have said they are virtually certain that Israel's intelligence agency Mossad was behind the assassination, but Israeli Foreign Minister Avigdor Lieberman has said there was no proof his country carried out the killing.

On Feb. 15, Dubai police chief Dahi Khalfan Tamim said 11 European passport holders are suspected to have been involved in the killing of al-Mabhouh.

Dubai police on Wednesday released a list of 15 additional names and photos of people allegedly involved in the assassination.