PHILADELPHIA CITY — Four malnourished mentally disabled adults were found chained to a boiler in a locked Tacony basement room that was too small for an adult to stand up straight in and also reeked of waste from the buckets they used to relieve themselves, Philadelphia Police said Sunday.

And one of the people accused of abusing them reportedly served time for a 1983 murder conviction.

Linda Ann Weston, 51, who was described as the ringleader of the alleged abuse, served four to 10 years for murder, cops said. Police didn’t immediately have details about that past conviction.

Weston and 47-year-old Thomas Gregory, and 49-year-old Eddie Wright, who is homeless, allegedly kept the disabled adults in horrid conditions, cops said.

Officers were investigating a report of squatters when they found three men and a woman in a 15-by-15-foot room behind a steel door that was chained shut.

Police are investigating the possibility that the suspects were trying to make money through access to the victims’ Social Security or disability checks, Little said. It wasn’t clear how they knew the victims.

The 29-year-old woman and the men, who are 31, 35, and 41, have the mental capacity of 10-year-olds, police said. They were taken to a hospital for treatment. Little said the victims appeared to have no physical problems other than malnourishment.

They are now in custody of the state being fed and taken care of.