WHEN police freed four mentally disabled people from a filthy sub-basement dungeon in Tacony, they had no idea that a severely beaten and tortured 19-year-old woman was imprisoned in an apartment closet three floors above.

For years, Beatrice Weston had suffered - and miraculously survived - beastly abuse at the hands of her captors: Her skin was seared with a heated spoon; her ankles were pocked with bullet-shaped wounds from being shot repeatedly with a pellet gun; her broken bones had barely healed before new fractures were inflicted; her malnourished frame was covered with bruises, according to police.

"I've never seen anything like this before in a living person," Police Commissioner Charles Ramsey said yesterday. "It's just remarkable that she is alive. . . . When we talk about that kind of cruelty to somebody, over and over and over again, there is no penalty, and I repeat, no penalty, that is too harsh for the people who did this."

Beatrice's rescue was the latest gruesome revelation in a suspected Social Security fraud scheme that spans at least four states.

A man who identified himself as a younger brother of Linda Ann Weston's told two local TV stations yesterday that she had forced him and other younger siblings to have sex with each other when they were children. Weston cared for her siblings after their mother died when Weston was 15. She also beat them, denied them food and sometimes tied them up for more than a day, according to the brother, who was not named in the reports on Channels 6 and 10.

Mayor Nutter described the case as a "tangled web of horror."

"This is sheer madness," the mayor said. "I think this is quite possibly one of the most visible signs of man's inhumanity to man."

Yesterday, police arrested Jane McIntosh, 32, a daughter of alleged scheme ringleader Linda Ann Weston, 51. McIntosh's arrest came four days after police discovered four mentally disabled victims, ages 29 to 41, in the sub-basement of an apartment building on Longshore Avenue. The victims were given little food and were forced to urinate and defecate into buckets.

In addition to McIntosh and Weston, prosecutors have charged Gregory Thomas, 47, described as Weston's boyfriend, and Eddie Wright, 50, with kidnapping and related offenses.

Beatrice had been locked in a closet inside McIntosh's second-floor apartment. Sometime after police discovered the four victims - one of whom was chained to a boiler pipe - Beatrice's captors moved her to a house in the city's Frankford section, police said.

Beatrice, who was in Weston's custody, is the daughter of Vicky Weston, one of Weston's sisters. Investigators are trying to determine how Weston, who was convicted of murder in 1984, gained custody of Beatrice nearly a decade ago.

"She was missing since the age of 8 from her birth mother," Lt. Ray Evers said at an afternoon news conference at City Hall. "There was a family feud between Linda Weston and Vicky Weston. . . . Court papers were given to Vicky Weston in reference to Linda Weston taking custody."

Evers later said that investigators had not found any official court paperwork awarding custody of Beatrice to her aunt.

Reached last night, Kevin Dougherty, administrative judge of Family Court, said that he was unaware of any question over custody.

A close relative of Vicky and Linda Weston's, who asked not to be identified, said that Vicky had suffered a head injury when struck with a baseball bat about 10 years ago and couldn't care for Beatrice.

Weston and another sister, Venus Weston, were convicted of murder in the 1981 starvation death of Bernardo Ramos. Ramos was the father of Venus Weston's unborn baby. The sisters beat Ramos with a hammer, tied him up and locked him in a closet after he said he wouldn't support the baby. Both sisters served prison time.

Police in Philly received a missing-person report on Beatrice in 2009. It was unclear whether Beatrice's mother or another relative had reported her missing. At the time, Beatrice was living with Linda Weston outside Pennsylvania, Evers said.

Police believe that Beatrice and the four mentally disabled adults arrived in Philadelphia about Oct. 3. Their captors drove them here from West Palm Beach, Fla., in two cars. Police said that Beatrice hadn't lived in Pennsylvania for six to eight years.

Tuesday night, police took Beatrice to an undisclosed hospital. She remains in protective custody. Authorities also placed six children, ages 2 to 17, under the care of the city's Department of Human Services. Police believe that two of the children, a 2-year-old boy and a 5-year-old girl, belong to Tamara Breeden, one of the four people locked in the Tacony dungeon. The children's father is one of the other victims.

Police said that they will conduct DNA testing to verify that Breeden is their mother. They also will use DNA testing to help determine the parents of the other four children. Some of the kids were extremely malnourished; Ramsey said that the 2-year-old looked more like a 6-month-old.

DHS spokeswoman Alicia Taylor said that the children were placed in foster care after medical evaluations.

"It was really about getting a roof over their heads and making sure they had a warm bed to sleep in [Tuesday] night," Taylor said.

Beatrice Higgins, of Hawthorne Street near Margaret, in Frankford, said that she rented her three-bedroom house to Linda Ann Weston about 10 years ago. She said that Weston, her boyfriend, Thomas, and her daughter lived there with a "bunch" of children. They wrapped a chain around the doorknob on the inside of the front door so that no one could get inside, she said.

"She [Weston] was on drugs and her boyfriend was crazy," Higgins said. "They set my house on fire. They said it was an electrical fire on the third floor, but there was no electrical problem. There was nothing wrong with the outlet."

"She told me the kids were on SSI and that's how she paid the rent - the kids' SSI checks."

After the fire, Higgins had them evicted. "They left in the middle of the night and there was nothing but rats in the house," she said.