A Calvert County woman accused last year of imprisoning her severely retarded sister in a bare room filled with filth has pleaded guilty to an abuse charge, the Calvert County state's attorney's office said this week.

Wenderland Bernita Broome, 41, of Lusby, pleaded guilty to one count of abuse of a vulnerable adult Friday in Calvert County Circuit Court. She had previously entered a plea of not criminally responsible. Broome changed her plea after she underwent a psychiatric examination and was found mentally competent.

Police went to Broome's outwardly tidy home in Lusby on Sept. 22, 1998, after an anonymous tip suggested they should check on the welfare of occupants of the house. A sheriff's deputy found Broome's sister, now 40 years old, in a nearly empty room, naked, unkempt and covered in excrement.

Broome later told police that she had been locking her sister in her room for up to five days at a time for the past 19 years and that she also had locked her 91-year-old father in the house, according to court records.

She was charged with two counts each of false imprisonment and abuse of a vulnerable adult. The imprisonment charges will be dropped at the time of her sentencing on Jan. 4, the state's attorney's office said. Broome faces up to five years in prison.