A Russian investigative journalist, who recently wrote about the deaths of Russian mercenaries in Syria, has died after falling from his 50th-floor balcony in the city of Yekaterinburg.

Maxim Borodin, 32, was found badly injured on the pavement under his balcony and taken to a hospital, where he died Sunday, according to his employer, the news website Novy Den (New Day).

Local police said they did not see any foul play, but his death prompted intense speculation among friends and colleagues.

Borodin’s friend, Vyacheslav Bashkov, wrote on Facebook that Borodin contacted him early in the morning on Wednesday, the day before the fall, and told him that there was a man with a gun on his balcony, and that several others in masks and camouflage clothing were lurking in the stairwell leading to his apartment building.

Bashkov said that Borodin had called back an hour later and said he had been mistaken and that he thought the armed men were probably taking part in a training exercise.

Borodin regularly covered high-profile corruption cases and crime in Russia. In February, he broke a story about Russian mercenaries who died in an armed confrontation with U.S. forces near Deir-Ezzor, Syria.

Last year, he gave an interview to a Russian independent channel TV Rain and talked about the controversial film Matilda, then was subsequently hit on the head by an unknown assailant with a metal pipe.

Russia ranks first on the European Federation of Journalists list of countries with the highest number of journalists murdered in Europe.

Since 1992, 38 journalists have been murdered in Russia, according to the U.S.-based Committee to Protect Journalists. Most of those cases remain unsolved.