New London police said they seized an AR-15 rifle and 30-round magazine from a city man after a teen he is accused of sexually assaulting disclosed in the summer of 2017 that she was afraid he would shoot her.

Robert M. Brown III, 34, of 190 Vauxhall St., who has been incarcerated on charges of second-degree sexual assault, first-degree threatening and risk of injury to a minor since September 2017, was arrested on the gun charges when he appeared Monday in New London Superior Court. The new charges are two counts of criminal possession of a firearm, illegal possession of an assault weapon, illegal possession of a large-capacity magazine and illegal possession of fireworks.

According to arrest warrant affidavits written by Detective Joshua Bergeson, police began investigating Brown after the Department of Children and Families notified them in July 2017 that a 13-year-old girl disclosed that Brown had sexually assaulted her. The alleged victim told police that Brown had been sexually touching her for years. She said he had two guns, had taken her shooting with him and that she was scared he was going to shoot her.

Brown could not legally own guns because he was convicted of a felony narcotics charge in 2008, according to the affidavit in the gun case. He was arrested on the sexual assault charges in September 2017 while police continued to investigate the weapons allegations.

In August 2017, police searched Brown's house and said they seized from his bedroom a blackjack (club), three BB guns, a dirk (or dagger), throwing knives, a BB gun rifle, a pellet gun rifle, a white trash bag full of fireworks, cases for a Bushmaster rifle and 9 mm handgun, ammunition, gun cleaner and a brown box addressed to Brown containing a "Drop-in Battle Rail" rifle part for a Bushmaster Model XM15-ES2. The rifle is an AR-15 and meets the definition of an assault weapon under Connecticut law.

The police questioned Brown's girlfriend, who said she purchased the rifle five years earlier for protection. She said she went shooting once with Brown and fired the rifle, but did not like it because it was too loud and powerful. She said she never shot it again. She admitted that after DCF got involved because of the sexual assault allegation against Brown, they brought the rifle to a friend of Brown who had a valid state pistol permit and lived in Waterford. The girlfriend said she believed having the rifle in the house was going to cause trouble with DCF.

The police contacted the friend, who turned over the AR-15 and accessories, including a light, scope and the 30-round magazine loaded with 27 live rounds of .223 caliber ammunition.

The girlfriend told police she and Brown had gone shopping for the gun at a store in East Lyme, and that she had to wait 14 days to pick it up after making the purchase. She said she had purchased ammunition along with the rifle, but had not bought anything since.

Police said they submitted the rifle and magazine to the state forensic laboratory for testing. A fingerprint impression lifted from the magazine was identified as a print from Brown's right ring finger. The rifle was test-fired four times and deemed operable. The spent casings from the test fire were entered into the National Integrated Ballistic Information Network (NIBIN) database and there were no associated hits, meaning the markings on the casings did not match others in the database. The police are awaiting the results of DNA testing.

Brown is being held in lieu of $200,000 at the Corrigan-Radgowski Correctional Institution. He has pleaded not guilty to all of the charges and is being represented by attorney M. Fred DeCaprio from the public defender's office. His next court date is April 16.

k.florin@theday.com