Russian oil executive's death brings attention to individuals who crossed the Kremlin and had strange outcomes.

 One analyst noted that there have been "a remarkable number of mysterious deaths of senior executives associated to the oil and gas industry" in recent months.

Major Russian oil executive's unexpected death has raised as many questions as it has provided solutions.

The largest private oil business in Russia, Lukoil, reported that Ravil Maganov, 67, "died away following a severe illness" on Thursday.

However, according to Reuters, which cited two persons familiar with his demise, he passed away after jumping out of a window at Moscow's Central Clinical Hospital. He may have been trying to smoke when he fell to his death, according to sources in the Russian media who spoke on condition of anonymity.

Maganov's family has not commented on his death, and NBC News has not confirmed how he passed away. The hospital, the police, and the Investigative Committee of Russia all denied requests for comment.

However, a number of Western analysts have pointed out that Lukoil, the nation's second-largest oil producer, spoke out against Russian President Vladimir Putin's war and demanded a stop to it a few days after his forces invaded Ukraine.

Maganov's death has been linked to no political activity, but several others who chose to cross the Kremlin have passed away unexpectedly and for unknown reasons.

Risky enterprise

According to John Lough, an associate fellow at London's Chatham House think tank, "there have been a remarkable number of mysterious deaths in recent months of senior executives affiliated with the oil and gas industry." Lough told NBC News via email on Thursday.

According to Lough, an expert on Russian politics, "it is reminiscent of the banditry of the 1990s in Russia during the initial phase of privatization after the collapse of the USSR."

Maganov's demise comes after the deaths of seven other top Russian energy executives since the year's beginning. One of them was his former senior Lukoil executive Alexander Subbotin, whose death was found in a country house's basement in the Moscow area in May, according to the local authorities.

Vladislav Avayev, the former vice president of Gazprombank, Russia's third-largest bank, as well as other senior executives from the natural gas behemoths Gazprom and Novatek have also passed away.

According to Lough, "this shows there is some severe infighting going on in the sector related to access to money flows."

The International Crisis Group's program director for Europe and Central Asia, Olga Oliker, claimed that using the word "trend" to characterize the deaths was incorrect. According to her, there have been enough examples to support the claims that either Russian state policy permits political killings or that it lacks oversight of its security forces and is unable to stop them.

"There have been enough cases that those who look to be at odds with Russian leadership may well be concerned about possible threats to their lives," she said.

Kremlin opponents

Police claim that former deputy prime minister Boris Nemtsov was assassinated in February 2015, the day before a planned demonstration against Putin's government, on a bridge close to the Kremlin.

Nemtsov was a harsh opponent of Putin, criticizing the ineffectiveness of his administration, widespread corruption, and the Kremlin's approach to Ukraine. Following his passing, a study he was working on detailing Russia's military involvement in the conflict in eastern Ukraine and the annexation of Crimea was made public.

Although Nemtsov's murder resulted in the conviction and imprisonment of five men, his passing left the country's opposition without a leader and sparked outrage among detractors who accused the Kremlin of cultivating a climate of intolerance toward any form of dissent and dubbed the killing an assassination.

Critics of the Kremlin and Western media compared his passing to that of renowned investigative journalist Anna Politkovskaya, who was fatally shot in October 2006.

Despite multiple instances of harassment and violence, Politkovskaya was well-known for her critical reporting on the conflict in Chechnya. She also penned a book critical of Putin and his campaign there, detailing extensive abuse of civilians by government forces.