Four masked attackers stormed the office of a street cleaning company in western Moscow early Tuesday, beating up the sole security guard and setting fire to the building, RIA-Novosti said.
An unidentified body was discovered in the office of the Logos-K firm after the fire was extinguished, the report said.
The guard, 67, was hospitalized after the beating, Lifenews.ru said.
The wooden building was destroyed by the fire along with seven street-cleaning trucks, a law enforcement source told RIA-Novosti. Police did not name any suspects Tuesday.