The UK investigation into what killed a Lancashire couple who died in Egypt could take "several months", a senior coroner has warned.
A Home Office pathologist began examining the bodies of John and Susan Cooper, from Burnley, on Thursday.
The Coopers died on August 21 while staying at the Steigenberger Aqua Magic Hotel in the Red Sea resort of Hurghada.
Their daughter, Kelly Ormerod, has said she has "no faith" in the Egyptian authorities, which reported that E.coli killed her parents.
Egypt's chief prosecutor Nabil Sadek said forensic examinations showed Mr Cooper suffered acute intestinal dysentery caused by E.coli, and Mrs Cooper suffered a complication linked to infection, likely to have been caused by E.coli.
He said the bodies of the couple showed "no criminal violence".
Dr James Adeley, senior coroner for Lancashire, said: "In view of the concerns raised by this case, analysis and evaluation of the findings at post-mortem and the associated samples may take some weeks or possibly several months to analyse.
"These results will need to be compared with the findings from the Egyptian investigation, when these are available to the Home Office pathologist and the coroner."