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A Russian billionaire has died in England after being mowed down in a three-car smash-up — and a friend is questioning whether it was a hit job, according to reports.

Tycoon Dmitry Obretetsky, 49, died in a hospital five days after he was knocked down while walking his dog near his home in Surrey on Nov. 25, according to the Sun. His dog, Oscar, also died in the crash that police say involved three cars.

Police have not made any arrests — but a Russian friend and associate questioned whether the father of three was deliberately killed.

“You know, people drive cars very carefully” in Britain, Pavel Borovkov told the Russian news agency Life.

“I don’t exclude that he was specially knocked down,” he claimed.

Borovkov paid tribute to the tycoon as “a wonderful friend and colleague, an understanding and friendly person.”

“Dmitry was a man of diverse interests — he did not focus only on business,” he said, recalling his friend’s love of soccer along with hard rock, calling him “a fan of Ozzy Osbourne.”

Obretetsky was reported to be a billionaire who made his fortune in Volgograd after the fall of the Soviet Union before moving to the UK eight years ago, the Sun said.

“We know very little about what happened,” his consulting company LLC Advant told the Sun. “Of course, this is a great loss and tragedy for all of us.”

The drivers of all three vehicles involved in the accident have spoken to police and no arrests were made, according to the Telegraph.

“We are continuing to investigate the circumstances around the collision,” a Surrey police spokesman told the paper.