The death of 43-year-old Carmelo Cuschieri in Cospicua on Friday is being treated as a "query murder" until the results of histological and toxicological tests are available in a few weeks` time, sources said.

The results would show whether Cuschieri died of a drug overdose, as has been suspected, or if he was murdered.

The sources said the case started off being treated as a possible overdose, but whether there was a high level of drugs in the victim`s body would be determined in a few weeks from the toxicology tests.

Evidence of strangulation marks on the neck indicated that some form of pressure had been applied to it. However, histological examinations still had to be carried out to determine whether the evidence of manual pressure on the neck, which was not self-inflicted, was related to the death.

Given the circumstances and strong suspicions, the case was not clear-cut, the sources said.

Magistrate Noel Cuschieri was, therefore, informed to start investigations because, if the cause of death subsequently turned out to be strangulation, the police would have lost two precious weeks.

The magistrate has appointed forensic expert Mario Scerri and members of the substance abuse unit to assist him.

The corpse is today being re-examined for bruises that show up after death.

Cuschieri, who was single and lived alone, was found dead on a pavement at the corner of Oratory and St Roque streets at around 11 p.m. The police had been in contact with the man in connection with drugs on several occasions, police sources said.

A number of people interviewed by police in connection with the death said they had seen Cuschieri walking along with his dog when he fell down and died. The witnesses reported that he was walking unsteadily before he fell.

Police investigations are being carried out by Assistant Commissioner Michael Cassar and Inspector Jeffrey Azzopardi.