Updated

A Russian lawyer linked to a case exposing corruption in Moscow plummeted from his fourth-story apartment on Tuesday -- as one of his top clients called it "extremely suspicious."

Nikolai Gorokhov, 53, fell from his fourth-floor apartment on Tuesday as a crane was lifting a large bathtub into his home.

"They were lifting a Jacuzzi through the window," according to Anastasia Berezina, 22, a neighbor who called an ambulance for Gorokhov. Berezina said that the equipment Gorokhov and other workers were using was "ramshackle," The Associated Press reported. Russian media also described it as an accident, reporting that a rope snapped.

RUSSIA TO ISSUE VERDICT IN DEAD LAWYER'S TRIAL

However, Gorokhov’s former employer, British businessman Bill Browder, suggested this may not have been an accident.

"It is extremely suspicious," Browder told The AP by telephone from London, suggesting the fall could be related to Gorokhov's work challenging President Vladimir Putin's government. "Gorokhov is a serious problem for the Putin regime as he has spent the last seven years exposing their complicity in the death of Sergei Magnitsky."

EVEN AFTER DEATH, SOME IN HISTORY HAVE FACED CONVICTION, 'EXECUTION,' AND EXONERATION

The family of Sergei Magnitsky, a Russian whistleblower who died in jail in 2009, had hired Gorokhov. The attorney was due to represent Magnitsky’s mother Wednesday in a Moscow court and was acting as a witness in a U.S. money laundering case.

Browder said that Gorokhov was determined to fight the Moscow court’s refusal to investigate organized crime.

Magnitsky died in a Moscow prison at the age of 37 after accusing officials of stealing $230 million via tax rebates.

Supporters said Magnitsky died from a severe beating, the BBC reported, but official records showed that he died of heart failure and toxic shock from untreated pancreatitis.

His death -- and the exposed corruption -- weakened relations between Moscow and the West.

The U.S. passed the Magnitsky Act in 2012 that sanctioned five Russian officials involved in alleged human rights violations in the Magnitsky case.

The Associated Press contributed to this report.