A Russian investigative reporter who had written about mercenaries in Syria has died after a mysterious fall from his balcony.

Maxim Borodin

Maxim Borodin died on Sunday after falling from his fifth floor apartment in Yekaterinburg three days earlier, according to New Day, where he worked.

The outlet reported that the 32-year-old reporter never regained consciousness after the fall, which it noted had occurred under “as of yet unexplained circumstances.”

Borodin’s editor, Pavelina Rumyantseva, told MBK Media that there was no reason to suspect suicide and that she will give information if there are any signs of criminal wrongdoing found in his apartment.

The reporter had recently published information about mercenaries from the Yekaterinburg region being among those killed in Syria during a U.S. airstrike. CIA Director Mike Pompeo has said that the strike left “a couple hundred” dead.

Russia has not given a death toll but confirmed that some of its citizens had been killed. They were believed to be working for the Wagner Group company linked to Yevgeny Prigozhin, the Kremlin-connected businessman accused by American prosecutors of running a troll farm to influence the U.S. election.

The information department of the Sverdlovsk region praised Borodin as “experienced and dedicated to his work” after his death, which is the latest in a string of investigative reporters.

Daphne Galizia, a Maltese blogger who reported on her government’s alleged ties to foreign money with the help of the Panama Papers, was killed in a car bomb explosion in October.

Jan Kuciak, a Slovak journalist investigating alleged Italian mafia theft of EU funds and tax fraud by businessmen linked to the ruling political party in the Eastern European country, was shot dead along with his girlfriend in February.

A group of international journalists calling itself Forbidden Stories announced Sunday that media outlets from around the world had continued the work of Galizia’s investigations.