SADDLE BROOK - A convicted sex offender was arrested on weapons and assault charges after police responded to what began as a domestic disturbance in Saddle Brook Saturday night.

Authorities arrived at a home on Bell Avenue at around 8 p.m. after police say Robert Sunday was threatening his girlfriend and her two adult daughters with a rifle.

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Sunday, who is a registered level 2 sex offender from a 1993 sex assault, was arrested on weapons and assault charges. After he was taken away, police discovered the rifle he allegedly used to threaten the women, plus eight more guns.

In the basement, authorities say they found a metal box that contained what appeared to be about 10 pipe bombs and a grenade.

Sunday, 51, was being held on $100,000 bail in the Bergen County Jail. He is charged with two counts of aggravated assault with a weapon and an illegal weapons possession charge.

Police say Sunday may face more charges as they continue their investigation.