A Petaluma man on probation was arrested Wednesday night at his home on suspicion on having bomb-making materials and ammunition, police said.

At 8:41 p.m., officers searched the home of Robert Brusell, 62, on the 100 block of Novak Drive in Petaluma without a warrant as part of his probation terms.

Inside, Petaluma police found a battery-operated electrical panel with gunpowder and three unused road flares; 22 empty 12-gauge shotgun cartridges with gunpowder, pellets and wadding removed and separated; and a small amount of methamphetamine.

Brusell told officers he intended to make a gunpowder rocket, but was unable to explain why he had other materials.

Police determined there was no safety risk to the area because of the amount of materials, which weren’t assembled. All of the items were removed.

Brusell was arrested on suspicion of possession of a controlled substance, violation of probation and being a prohibited person in possession of ammunition. He was booked into the Sonoma County Jail.

He was on probation for misdemeanor DUI and possession of drug paraphernalia. He is also a convicted felon, which prohibits him from having ammunition.