Three people have been arrested in Philadelphia after a janitor found four adults, each with "the mental capacity of a 10-year-old," chained to a water heater in a tiny room in "deplorable conditions." All four were malnourished.

Police have a 51-year-old Texas man, a 48-year-old man and a 51-year-old woman in custody. The four victims (three men and one woman) are between 29 and 41 years old, and may be from Texas. They appear to have lived with one of their alleged captors in Florida for a year before arriving in Philadelphia in early October—where they were imprisoned in an apartment in which relatives of their female captor lived, apparently with no knowledge of the abuse.

The alleged abusers will be named when police file formal charges against them. All four victims are under observation and are in stable condition.

[Philadelphia Inquirer, image via Shutterstock]