Sergey Protosenya, a Russian oligarch who formerly served as deputy chairman of gas company Novatek, was found dead by hanging on April 19 in a villa on the Catalonian coastline, local outlet El Punt Avui reported. Mossos, the local police force, announced last week that the bodies of Protosenya’s wife, Natalya, and teenage daughter, Maria, were also found at the scene, and that the two had died by stabbing. Mossos also said that the three deaths occurred while the family was on their Easter vacation.

Spanish authorities suspect that Protosenya murdered his family members, then killed himself, according to Spanish news outlet Telecinco. 

But Protosenya’s son, Fedor, who was in France at the time of the deaths, doesn’t believe that his father murdered anyone. 

“My father is not a killer,” Fedor told U.K. newspaper the Daily Mail on Tuesday.

Fedor Protosenya is convinced of his father’s innocence, saying that he “could never harm” his family and alleging that all three were victims of a homicide.

“He loved my mother and especially Maria, my sister,” Fedor said. “He could never do anything to harm them. I don’t know what happened that night but I know that my dad did not hurt them.”

Fortune was not able to contact Protosenya.

Fedor was not the first to challenge the leading murder-suicide theory of the case. 

Novatek—Russia’s second-largest gas company—publicly came out with a statement last Thursday defending its former executive and casting further doubt on the prevailing theory.

The company remembered Protosenya—who was employed there between 1997 and 2015—as a “wonderful family man” and disputed the murder-suicide premise.

“We are convinced that these speculations bear no relation to reality,” the statement read.

The scene of the crime reportedly lacked fingerprints on the murder weapons used against Natalya and Maria, and there was no blood on Protosenya’s body, according to El Punt Avui, a local newspaper. Protosenya was described by neighbors as largely leading a “quiet life” and having no history of “complaints of gender-based violence,” Telecinco reported. 

The case of the Protosenya family is the latest in a string of deaths of Russian elites over the past few weeks.

The bodies of the Protosenya family were discovered only a day after news broke that Vladislav Avayev—former vice president of Gazprombank—as well as those of his wife and 13-year-old daughter were found dead in their Moscow apartment. Avayev was found with a pistol in hand, and the case is also being treated by authorities as a murder-suicide, as reported by Tass, a Russian state-owned news outlet.

In March, billionaire businessman and owner of wholesale company Medstom, Vasily Melnikov, was also found dead in his home in the city of Nizhny Novgorod alongside the bodies of his wife and two sons. Police investigations have determined this case to have also been a murder-suicide, according to Russian news outlet Kommersant.

Russian oligarchs Alexander Tulyakov and Leonid Shulman were also found dead earlier this year in their homes near St. Petersburg. Both were former executives of state-owned gas company Gazprom, and evidence at both scenes suggested suicide. Shulman’s body was found with a suicide note, while Tulyakov was found by his partner hanging in his garage, according to U.K. outlet the Mirror.