The death of a Russian weapons expert, whose lifeless body was found in a St Paul's Bay apartment last Wednesday, appears to have been an accident, according to sources.

However, police are not ruling out the possibility of foul play at this stage since they are waiting for the outcome of the magisterial inquiry and further forensic tests, including toxicology results.

Alexander Pikayev, 48, was found lying on the floor in his apartment in Triq Buġibba, with a wound to his head. Police were called to assist after relatives could not contact him.

An autopsy revealed that he suffered from a fractured skull and intracranial haemorrhage.

"It seems that he slipped and hit his head with the jamb of a door in the apartment. A dent on the jamb supports this theory," sources said, adding that results of further tests were still pending.

The fact that the apartment was locked from the inside and nothing inside was disturbed reinforced the belief that it was an accident, the sources added.

Dr Pikayev was holidaying in Malta with relatives, including his brother. They arrived a few days before the accident and had a three-month travel visa. It is not clear how long he intended to stay.

Dr Pikayev was an internationally recognised expert on weapons of mass destruction disarmament and non-proliferation, and was one of the most frequently cited Russian experts in the field.

He was the director of the Department of Disarmament and Conflict Resolution at the Moscow-based Institute of World Economy and International Relations.

He also headed the James Martin Centre for Non-proliferation Studies' Non-proliferation Project in Russia. He worked at the Russian Duma Defence Committee as a senior professional staff member.

Mr Pikayev's mysterious death evoked memories of the murder of Alexander Litvinenko in London four years ago. The former KGB officer died after weeks of debilitating illness triggered by thallium poisoning.