Major crime squad detectives have taken over the investigation into the death of British pop singer George Michael. Picture: Miguel Medina

Detectives fear the star, found dead on Christmas Day aged 53, died from a drugs overdose.

A leading picture agency has been ordered to hand over all shots taken near the singer’s home before Christmas to help identify who came and went before his death, The Sun has reported.

The ex-Wham! star’s shock death at his riverside mansion in Goring, Oxfordshire, is still being treated as “non-suspicious”.

But detectives from the Thames Valley Police Major Crime Unit, whose cases include rapes and murders, have now been called in to the probe after a post-mortem proved inconclusive.

A source said: “The investigation is now picking up a bit of speed.

George Michael was found dead on Christmas Day, aged 53. Picture: SuppliedSource:Supplied

“Officers from the Major Crime Unit have begun asking questions of those who were in the area at the time George died and the days before.

“They want to build up an idea of what George’s last seven days were like and who came and went.

“These individuals now handling the day-to-day inquiries have worked on some very serious crimes so are well placed to assist with this.”

It comes amid fears George, whose fortune was estimated at more than £105 million (AUD$177 million), died from an overdose of illegal or prescription drugs.

A post-mortem last week failed to establish his cause of death, with toxicology tests now being carried out.

The star was found dead at his home in Oxfordshire. The cause of his death remains a mystery. Picture: Carl Court/Getty ImagesSource:Getty Images

The star had a well-documented history of drug abuse and his cousin revealed he was treated for crack cocaine addiction as recently as 2015.

After his death his family denied claims that George was also battling a heroin habit.

But one retired senior police said: “Given his history, there must be a possibility that drugs, illegal or otherwise, could have been involved in his death.

“Because of his high profile and wealth it makes absolute sense for the Major Crime Unit to investigate the full circumstances while they wait for the ‘tox’ tests to come back.

“It does not mean that he did die from drugs but until it is proved otherwise they cannot rule it out and must investigate appropriately.”

This pop career spanning three decades made him popular throughout the world. Picture: Justin TaallisSource:AFP

George’s boyfriend Fadi, 40, spoke to local officers after finding his lover’s body on Christmas Day. But it is understood elite detectives wish to question him again shortly as a witness — along with relatives, George’s housekeeper and neighbours.

Photographers from Flynet Pictures, who were working in nearby Goring, have also been quizzed.

Police have asked the Kent-based firm for their photos as they believe they may help identify who visited George’s home before his death.

A Flynet spokesman said last night: “We can confirm that we are helping the police with their investigation.”

Michael’s Australian boyfriend Fadi Fawaz will be reinterviewed by police as the investigation continues. Picture: TwitterSource:Supplied

There is no suggestion that Flynet or others interviewed are under suspicion.

Questions have been raised over conflicting accounts as police prepare to hand over a case file to Oxfordshire Coroner’s Office.

Hairdresser Fadi had originally claimed he spent the weekend at George’s house and found him dead on Christmas Day.

He said at the time: “Everything had been very complicated recently, but George was looking forward to Christmas and so was I.”

But Fadi later said that he slept in his car the night before he found him dead.

The legend at the top of his game in 1988. Picture: Rob Verhorst/RedfernsSource:Getty Images

He was pictured buying coffee on Christmas Eve near George’s home and it was unclear why they spent the night apart.

Last week tweets from his account claimed George had tried to kill himself several times and he finally succeeded.

The tweets, which stunned the star’s fans, were sent in the early hours of New Year’s Day before they were deleted and the account shut.

George’s publicist labelled them “speculation” but did not deny the claims.

This story first appeared in The Sun and was republished with permission.