Police investigating the case of a young man who died of a suspected drug overdose on Wednesday made six arrests.

The youth, 22, was found dead by his brother at his residence in Toni Bajada Street, St Paul's Bay.

Sources said it was immediately suspected that the cause of his death was a heroin overdose after related material, including syringes, were found next to the body.

The breakthrough in the case came when the police Drugs Squad arrested a 30-year-old man suspected of selling the drugs to the young man.

In fact, the sources said a search of the man's apartment in Msida yielded about seven grammes of heroin, a small amount of cannabis and suspected ecstasy pills, together with two weighing scales and other material connected to the trafficking and abuse of drugs.

Later in the day, another five people, four men and a woman, whose ages vary between 17 and 29, were also arrested.

Sources said the four were suspected of buying drugs from the same person.

Meanwhile, an autopsy on the youth yesterday established that he had died of pulmonary oedema, the accumulation of water in the lungs and a common symptom of overdoses.

It is understood that the young man had recently dropped out of a drug rehabilitation programme.

Overdoses are unfortunately common in such cases because the patients' tolerance to drugs drops throughout the programme, exposing them to an overdose if they use the same dose as the one they were used to before starting rehabilitation.