A Russian investigative journalist who died in a mysterious fall from his fifth-floor apartment complained about masked security men surrounding his flat just one day before his death, according to a friend. Maxim Borodin, whose work included reporting about the deaths of Russian mercenaries in Syria, was found badly injured by neighbors in the city of Yekaterinburg on Thursday and died at a hospital. Local officials said the incident was unlikely to be criminal in nature, but the chief editor of Novyy Den, where Borodin worked, said he didn’t believe his death could have been an accident. Now Boridin’s friend, Vyacheslav Bashkov, has claimed the journalist contacted him a day before his death complaining that “someone with a weapon on his balcony and people in camouflage and masks on the staircase landing.” Regional authorities said the door of his flat had been locked from the inside, indicating that no one else had either entered or left the flat.