Fears have been raised that the illegal drugs being used by prison inmates may have been mixed with contaminating substances after four prisoners were taken to hospital suffering from chest pains last week, The Royal Gazette has learned.

Meanwhile Police have launched an investigation into the death of convicted bank robber Rupert Elroy Archibald, adding fuel to suspicions that the former Westgate Correctional Facility inmate's apparent heart attack last month was drug related.

The developments come after Home Affairs Minister Terry Lister revealed in the House of Assembly last week that a quantity of drugs had been found near the sink in a bathroom at Westgate on Tuesday.

He added that prison officers were not able to trace the narcotics to any specific individuals.

Last night, Home Affairs and Public Safety Permanent Secretary Robert Horton said three prisoners from Westgate and one from the Prison Farm were treated at King Edward VII Memorial Hospital after they complained of chest pains last week.

He said while three of the men were seen by physicians and released the same day, one of the Westgate prisoners was treated at the hospital for four days.

Mr. Horton said he could not reveal which day the men were taken ill but added that all of them are now in good health and are back in their respective prisons.

He said he had no knowledge of the incidents being related to drug use and added: "I could not possibly speak for the physicians as to what might have caused the chest pains."

Prisons Commissioner John Prescod could not be reached for comment yesterday.

However, a Westgate source said a high ranking Prison official had told him he suspected the problems to have been caused by the misuse of illegal substances.

And he said officials were worried that drug users inside Westgate were being supplied with heroin that had other substances added to it.

Police Media Relations spokesman Dwayne Caines confirmed that Police had been conducting an investigation into Mr. Archibald's death on July 15 after an autopsy was completed.

Police Coroner's Officer Insp. Phil Taylor said the results of the autopsy would remain confidential until it was felt they should be publicised and added that a date for an inquest had not been set.

Mr. Archibald, 41, was serving a 30-year prison sentence for a 1997 armed robbery at the Somerset branch of the Bank of Bermuda.

On the day of Mr. Archibald's death, Mr. Horton said he had no knowledge of any possible involvement of illicit drugs, although a source told The Royal Gazette otherwise.

But Mr. Horton explained that Mr. Archibald suffered a heart attack as he was being rushed to hospital by ambulance.

Although doctors and nurses administered life-saving measures, Mr. Archibald was pronounced dead shortly after his arrival, roughly an hour and a half after the initial report.