An allegedly drunk plumber whose identity remains unknown came to the director of a company which oversees technical maintenance and services for a city district, the Ren TV broadcaster reported.
The director reportedly attempted to kick the desperate man out of the office and, after a brief altercation, the intoxicated, angry plumber drew a deadly argument from his pocket.
The plumber then pulled the pin from the grenade and hurled it at the boss. The grenade detonated, injuring the director.
Local authorities launched an investigation into the incident, including how the drunk worker was able to get his hands on a live grenade. The identity of the company and the Moscow district have not been released.