Police arrested one man, and seized 80 pounds of marijuana, four guns and about $10,000 cash after responding to an alarm at a Manhattan Beach house, officers said Wednesday.

Officers made the discovery when they arrived at the house in the 1300 block of Marine Avenue about 4 p.m. Tuesday.

Police checked the doors, windows and exterior of the house for any sign of a crime, and found a sliding glass door at the rear that was unlocked. While checking inside for burglars, police saw a large amount of marijuana.

Finding no one inside, officers withdrew, obtained a warrant and searched the house. They discovered the marijuana, an assault rifle, three handguns and the cash, police said.

The resident, Stephen Scott Brown, who turns 31 on Saturday, arrived while police were investigating. He was arrested on suspicion of possession of marijuana for sale.

Brown posted $100,000 bail and was ordered to appear at Torrance court on April 13.

— Larry Altman