ROYAL Navy engineer Charlie Warrender, who was found dead while on active service in the Seychelles islands, had traces of heroin in his system, it has been confirmed.
But it is understood investigators are looking into the possibility that his drink may have been spiked as he and fellow crew members of HMS Richmond visited the island from their ship in May.
An inquest opening has heard the 22-year-old former Grimsby student from North Thoresby died from the combined effects of alcohol and heroin intoxication with positional asphyxia.
He was found dead at 6.30am near the docks in the main port of Victoria.
Seychelles Police said the death was suspicious because the serviceman had a head injury.
Toxicology tests later confirmed traces of heroin in his system.
Several crew members were out with the engineer technician on the evening before his body was found.
The coroner for Grimsby and North Lincolnshire, Paul Kelly, is awaiting a reports from the island police and the Royal Navy who have interviewed crew members.
A Royal Navy spokeswoman said Seychelles Police have primacy in the investigation.
She said: "The Royal Navy undertook an Immediate Ship's Investigation (ISI) into the circumstances surrounding this incident.
"The purpose of the ISI was to review the ship's leave and security policy at the time of the incident.
"This was not an investigation into ET Warrender's death, for which the Seychelles Police have primacy. Therefore, the ISI did not inquire into, assess or analyse any matters or material which may prejudice the findings of the Seychelles Police investigation.
"A review of the ISI is now being carried out to determine if there are any immediate lessons that should be identified."
The former Louth King Edward VI Grammar School pupil was serving on Portsmouth-based ship HMS Richmond, which was part of Operation Kipion in the Indian Ocean at the time.
At the time of the tragedy his family issued a statement describing Charlie as "a charismatic and loving young man, who made everyone who met him smile."
The family statement said: "He was extremely proud to serve in the Royal Navy and was thoroughly enjoying travelling the world, progressing his career as a Marine Engineer."
While on board HMS Richmond he played an active part in operations supporting UK Sovereign Territories in the South Atlantic, Defence Engagement with Chilean forces, counter narcotics duties in the North Atlantic and service in the Indian ocean.
Charlie was a former Franklin College student, who spent time with Humberside Engineering Training Association (HETA) in Stallingborough.
A guard of honour was held by The Royal Navy at his funeral in June at Grimsby crematorium.