A Neponset Avenue resident and his sister were arraigned on a variety of charges today after police arrested the man and found his pre-teen children alone in his apartment, the Suffolk County District Attorney's office says.

Johnny LaCourt, 33, was ordered held in lieu of $50,000 bail on charges of unlawful possession of a firearm, unlawful possession of a firearm with a defaced serial number, unlawful possession of ammunition, and possession of a Class B substance with intent to distribute, all as an armed career criminal. Jacqueline LaCourt, 34, had bail set at $1,000 on a charge of unlawful possession of ammunition, the DA's office says.

Prosecutors say C-11 drug detectives stopped LaCourt around noon on Saturday after he left his apartment at 37 Neponset Ave., as part of an ongoing investigation. Armed with a search warrant, they went to the apartment and knocked on the door:

"It was answered by a 7-year-old boy, who was home alone with his 2-year-old brother. Both were Johnny LaCourt's sons. Though neither child was suffering from any obvious injury, officers called for medical assistance and the children were transported to Boston Medical Center for evaluation. Boston Police are following up with a referral to the Department of Social Services.

"A search of the apartment turned up a digital scale, two boxes of plastic sandwich bags, nine bags of crack cocaine, an unloaded .32 caliber Smith & Wesson five-shot revolver with an obliterated serial number, 14 rounds of .32 caliber ammunition, and $320 in cash, all in Johnny LaCourt's bedroom.

"Also recovered pursuant to the warrant were a second digital scale and a backpack containing 543 rounds of ammunition in various calibers in Jacqueline LaCourt's bedroom."

The DA's office says Jacqueline LaCourt arrived in the middle of the search and that when detectives asked her why she had so much ammo, she said she was holding it for a friend.