The party-loving crown prince of Sharjah, scion to one of the seven emirates that make up the United Arab Emirates, was found dead in London on Monday morning.

He was buried in an elaborate ceremony in Sharjah on Wednesday as a story was published in The Sun newspaper in London claiming that he died after a drug-fueled party at his Knightsbridge penthouse.

Sheikh Khalid bin Sultan al Qasimi, 39, a fashion designer, was the second son of the emir of Sharjah, but was named crown prince after his brother, Sheikh Mohammed bin Sultan al Qasimi, died of a heroin overdose in 1999 at the family’s £3 million English manor house in Sussex.

The Sun, quoting an unnamed source, said the police found a quantity of Class A drugs at al Qasimi’s home after being summoned by an ambulance crew this week.

The source said: “There had apparently been a party where some guests were taking drugs and having sex. It is suspected that Sheikh Khalid may have died suddenly as a result of taking drugs. As well as the police inquiry, an urgent internal probe has been ordered and staff have been ordered to keep quiet.”

The crown prince, who studied architecture and fashion design at Central Saint Martins in London, founded an eponymous fashion brand, Qasimi, in 2016.

He had shown collections at London and Paris fashion weeks.

A statement on the Qasimi website said: “Khalid was praised for his tenacious yet sensitive exploration of social-political issues, particularly pertaining to the Middle East and its sometimes strained relationship with the West, a subject very close to his heart and upbringing.

“His goal was to create a world of beautifully crafted products infused with cultural, social, and political undertones to inform and inspire.”

Detectives are treating the new tragedy as “unexplained” and have made no arrests, The Sun said.

Khalid’s father announced three days of official mourning, saying that his son “is in the care of God" as tens of thousands of mourners flooded the streets for the funeral that began today.

It caps a bad few weeks for Emirati rulers. Last week, The Daily Beast revealed that the ruler of Dubai had been deserted by his wife, Princess Haya, who is believed to be hiding in London.