EAST MEADOW — Grenade launchers, assault rifles and marijuana were discovered at the home of a man accused of domestic violence, according to New York State Police. The cache was found at the Bernice Drive home of Michael Anderson, 27, who was arrested Friday, and included two grenade launchers, two assault rifles, several thousand rounds of military ammunition and other weapons, police said. It all started when a trooper conducting a traffic stop on Wantagh Parkway was approached by Anderson’s girlfriend who was “hysterical” and said she was being chased, according to police. While being interviewed, Anderson gave police permission to search his home and the cache was discovered, police said. Anderson has been charged with assault, drug possession and five counts of criminal possession of a weapon.