Three relatives of the mastermind behind the September 11 attacks, Osama Bin Laden, have reportedly died in a plane crash in the UK on Friday.

Four people passed away in the accident, British authorities confirmed Saturday.

The Hampshire Police said in a Facebook statement it believed those killed to be the mother, sister and brother-in-law of the owner of the aircraft — all Bin Laden family members. The three deceased were Saudi Arabian nationals, the police confirmed, and formal post-mortem examinations are ongoing. The plane's Jordanian pilot also died.

Update on the plane crash at Blackbushe Airport:The investigation into the plane crash at Blackbushe Airport yesterday... Posted by Hampshire Constabulary on Saturday, August 1, 2015

Arab media and NBC News named the relatives as Osama Bin Laden's stepmother Rajaa Hashim, his sister Sana bin Laden and her husband Zuhair Hashim.

Police said the Saudi-registered Embraer Phenom 300 executive jet crashed into a parking lot and burst into flames while trying to land at Blackbushe Airport in southern England Friday afternoon. The plane was flying from Malpensa Airport in Milan to the airfield about 40 miles (65 kilometers) southwest of London, which is used by private planes and flying clubs.

Police and the Air Accidents Investigation Branch launched a joint investigation.

Small plane crashed into car auction at Blackbushe airport pic.twitter.com/lxHLF76WIf — Nathan Greenwood (@NathanGFilm) July 31, 2015

Andrew Thomas, who was at a car auction sales center based at the airport, told the BBC that "the plane nosedived into the cars and exploded on impact." He said he saw the plane and several cars in flames.

"There was a loud bang and my son quickly came into the auction hall saying a plane had gone down," Joe Ramos told local station Eagle Radio. "We quickly went back out only to see a private jet had gone over the fence of the airport as it was trying to take off, but in fact it had clipped the fence, spun around and crashed into the cars."

The Saudi ambassador to Britain, Prince Mohammed bin Nawaf al Saud, offered condolences to the Bin Laden family on Twitter, without naming the family members.

سمو سفير خادم الحرمين الشريفين الامير محمد بن نواف يعزي أسرة بن لادن. pic.twitter.com/iHr1RlGWLC — Saudi Embassy UK (@SaudiEmbassyUK) July 31, 2015

Questions are being asked about the crash, which occurred in near perfect weather. "It doesn’t make sense to me as an ordinary pilot why something that advanced and easy to fly would bury itself in the auction ground at the end of such a long runway," Simon Moores, a flight instructor and pilot who has flown at the airport, told the Guardian.

Emergency services attend the scene of a plane crash next to Blackbushe Airport in southern England on August 1, 2015.

The plane's pilot was Mazen Salem al-Dajah, a Jordanian in his late 50s. His brother Ziad told The Associated Press that al-Dajah's family had been told of his death by a representative of the bin Laden family's corporation. He said al-Dajah received his pilot's license in California about 25 years ago and had been employed by the bin Laden family.

The bin Laden family, which is a rich, powerful force in the region, disowned Osama in 1994 when Saudi Arabia stripped him of his citizenship because of his militant activities. The al-Qaida leader was killed by U.S. special forces in Pakistan in 2011.

Additional reporting by the Associated Press