Toxic farm-strength insecticide was sprayed in the room next to where a British couple were found dead in an Egyptian hotel, according to reports.
John Cooper, 69, and his wife Susan, 64, died after being taken ill while staying in the Red Sea resort of Hurghada during a Thomas Cook holiday.
An investigation was launched after the pair died while staying at the Steigenberger Aqua Magic Hotel in late August.
And it has now been revealed that the room next to where the couple were staying was fumigated with the powerful insecticide "lambda-Cyhalothrin 5 per cent" just hours before they fell ill, the Times reported.
It comes after the Coopers’ daughter Kelly Ormerod, who was on holiday the couple, said there was a strange smell in their room and that their deaths are suspicious.
Thomas Cook said last week that e.coli had been found at the hotel where the couple were staying, but that this does not establish the cause of their deaths.
But neither the independent specialists who carried out the investigation nor a medical expert "believe that these results shed any light on the still unexplained cause of death of Mr and Mrs Cooper", the company said.
Mrs Ormerod, who had been on a break with the pair, from Burnley, Lancashire, has since questioned the Egyptian authorities' investigation efforts, saying the hotel room was not taped off until 24 hours after the deaths.
Speaking to ITV News last week, she said: "When we went into the room on the Wednesday, I noticed that the cleaners had been in.
"All the floors had been mopped, all the bedding had been changed and for those 24 hours maintenance were in and out quite often.
"If it happened over here it would have been taped off but the room wasn't taped off until I believe the Thursday so everybody and anybody could go in that room on that Wednesday."
She said she feared there could have been "crucial" evidence in the room which would now be lost.
"There was obviously evidence left over from my Mum and Dad in that room which I think was quite crucial as to why they possibly died," she said.
Mrs Ormerod said she now felt "disappointed" and "disheartened", adding: "I thought I'd have the results today and that Mum and Dad could come home."
She added: "Once they're home, I can start the next fight as to what the actual answers are."
Thomas Cook said in a statement: “We await the results of the Egyptian authorities’ investigation into the tragic deaths.”
Steigenberger has been approached for comment.