Emiliano Sala and pilot David Ibbotson were poisoned by toxic levels of carbon monoxide before their plane crashed into the English Channel, investigators have said.
The Cardiff City footballer was on his way to the club after signing a contract with them in January when the Piper Malibu aeroplane disappeared from radar.
An investigation was launched on the night of Monday 21 January following the disappearance, and the wreckage was located on the seabed on 3 February.
Rescue efforts retrieved Sala’s body from the wreckage, but the body of Mr Ibbotson has still not been found.
An update into the investigation by the Air Accidents Investigation Branch issued an update on Wednesday afternoon to reveal that toxicology tests on Sala’s body revealed that he had been exposed to harmful levels of carbon monoxide poisoning before his death.
Although tests cannot be carried out on Mr Ibbotson, it is “considered likely” that he was also exposed to similar carbon monoxide poisoning.
The statement read: “The AAIB has published a second Special Bulletin on the loss of Piper Malibu aircraft N264DB. This Special Bulletin highlights the danger of exposure to carbon monoxide in both piston and turbine engine aircraft.
“Toxicology tests found that the passenger (Sala) had a high saturation level of COHb (the combination product of carbon monoxide and haemoglobin). It is considered likely that the pilot would also have been exposed to carbon monoxide.
“When our investigation has concluded, we will publish a final report.”
The finding could explain how Ibbotson lost control of the plane, given that the main effect of carbon monoxide poisoning is a loss of consciousness.
The report explains that tests in Sala’s body returned a carboxyhaemoglobin (COHb) saturation level of 58 per cent, with any level of 50 per cent and above in a healthy individual considered potentially fatal and can result in seizure, unconsciousness or a heart attack.
It adds: "It is clear from the symptoms that exposure to CO (carbon monoxide) can reduce or inhibit a pilot’s ability to fly an aircraft depending on the level of that exposure."
Sala’s family issued an immediate statement following the release of the update, calling for the Air Accidents Investigation Branch to launch an immediate attempt to salvage the aeroplane wreckage for analysis, as it remains at on the Channel seabed.
Daniel Machover of Hickman & Rose solicitors, lawyer for the Sala family, said: “That dangerously high levels of carbon monoxide have been found in Emiliano’s body raises many questions for the family. How he died will be determined at the inquest in due course.
“The family believe that a detailed technical examination of the plane is necessary.
“The family and the public need to know how the carbon monoxide was able to enter the cabin. Future air safety rests on knowing as much as possible on this issue.
“Emiliano’s family call on the AAIB to salvage the wreckage of the plane without further delay.”
In February, an initial inquest hearing into Sala’s death at Bournemouth Coroners' Court heard that a post-mortem determined that he died of head and trunk injuries, though the full cause of death will not be determined until the investigation and inquest are completed.