Key pieces of evidence from the fatal Haut du Mont explosion are being examined at one of the UK's top laboratories as Operation Spire enters its next stage.
Investigators have gathered all the physical evidence from the site of December's fatal explosion at Haut du Mont flats which killed 10 people.
Some 700 exhibits have recovered.
Experts in the UK are examining the evidence at the HSE Science and Research Centre in Buxton for clues to what caused the explosion.
Officers have also carried out more than 900 lines of enquiry and taken more than 400 statements.
They continue to review CCTV footage and key witness statements.
Police completed their work at the scene a week ahead of schedule.
Senior Investigating Officer Alison Fossey says hopefully the good progress will continue.
"Of course we're now in the hands of the experts and the laboratories in the UK, but it's a significant milestone and there has been really good progress made by all concerned.
Although we continue to keep an open mind about the cause of the tragedy, our working hypothesis is a gas explosion.”
30 experts from GoCrisis are still at the site recovering personal belongings for the bereaved families and those who have been displaced.