01/10/2012 09:37 am ET Updated Mar 11, 2012

Shirley Mathis, Coral Springs Grandmother, Accused Of Chaining Grandson To Bed For Three Years

A Coral Springs grandmother is accused of chaining her mentally disabled 19-year-old grandson to his bed nightly for roughly three years, locking him and his younger brother in the room to sleep with only a small bucket in which to relieve themselves.

After an anonymous tip to adult protective services, CSPD officers arrived at the home of 58-year-old Shirley Mathis on December 26, along with child welfare investigators from both the Florida Department of Children and Families and the Broward Sheriff's Office. Upon entering the home, according to the complaint affidavit, they found the victim restrained in his bedroom with a heavy gauge metal link chain secured with five locks to a metal bunk bed frame, the other end secured around his waist with a combination padlock.

"I only loved him. I never abused him," Mathis later told WSVN. "It was for his own good and his own health and his own safety."

The room had a strong odor of urine, according to police, and the floor and mattress were covered in plastic. The teenager and his 14-year-old brother told investigators the door would be locked at night and then unlocked in the morning, with a small bucket provided for the pair to relieve themselves.

Alarmingly, Mathis was reportedly out of state visiting North Carolina with her fiance when investigators arrived to check on the children. While gone, she had arranged for family friend Kimberly Cooper to come over nightly and chain the teen to his bed, then lock the boys inside the room for the night before returning in the morning to let them out. But when police arrived at the home at 2:45 p.m., according to the affidavit, the teen was still chained to the bed and investigators had to call Cooper. She finally arrived at 4 p.m. to unlock him.

"It was very disturbing when I walked in to see a human being chained to bedpost as if he was an animal," said Coral Springs Police Lt. Joe McHugh.

The victim, who has a reported history of mental illness and post traumatic stress disorder, told police that he deserved to be chained to the bed and the restraints were for his own good. "[He] said he would leave the home in the middle of the night and break into neighboring homes to steal food if he was not chained," read the police report.

The teen became increasingly agitated when he learned he could not speak to Mathis and as officers questioned his family. After he grabbed a broken broomstick and attempted to attack an officer, investigators transported him to hospital under the Baker Act. "Based on my investigation, it appears [he] suffers from a developmental disability and/or mental illness to the point that his ability to perform the normal activities of daily living are restricted," wrote an officer.

Police also noted that the kitchen refrigerator was secured with a chain and padlock, and access to the garage where a second refrigerator was located was secured by a chain and padlock. The grandmother's bedroom and a sister's bedroom were also under lock and key. A great grandmother who also lives in the home was aware the boys being chained or locked in nightly, but only possessed keys to the kitchen refrigerator and garage. In a sworn statement, police say, she said she knew the boy did not like being chained.

After returning home from North Carolina, Mathis was interviewed by police. Investigators say she admitting to chaining her grandson to the bed every night since a 2008 incident in which he robbed another home, attempting to steal food. Mathis said the family's landlord threatened to evict them if the teen caused another problem, and she told WSVN that when the boy was previously in the care of his mother, the mother would lock him in a closet, where he would eat his own feces.

Cooper later admitted to police she had come up with the idea of chaining the boy to the bed, purchasing all the necessary hardware, and locking the boys up while Mathis was on vacation, according to the affidavit. Police say Mathis' fiance told them he initially thought the practice inhumane, but later concluded it was for the boy's own good and even chained him up himself on one occasion. Neither faces charges, McHugh said.

The teen's brother and sister refused to cooperate with the investigation, both saying he deserved to be chained to the bed. According to McHugh, all three siblings are now in the care of the child welfare services.

Mathis was arrested January 5, charged with aggravated abuse of a disabled adult, abuse of a disabled adult, aggravated child abuse, and false imprisonment/domestic violence. She posted $12,000 bond on January 8.