A Coral Springs woman has been arrested on charges that she chained her 19-year-old grandson to a bed nightly for three years, leaving a small bucket nearby for use as a toilet, according to an arrest affidavit.

Acting on an anonymous tip, authorities visited the young man’s home Dec. 26 and found him restrained by a thick chain that was locked to a metal bunk bed and wrapped around his waist, police said. Part of the chain wasn’t taut, giving the man limited mobility. Inside the bedroom was the bucket and a strong odor of urine, police said.

“It was extremely disturbing to see somebody discipline an individual in that manner,” said Lt. Joe McHugh, a Coral Springs police spokesman.

During police questioning, Shirley Roberson Mathis, 58, said she started chaining her grandson each night shortly after an incident in 2008, when he burglarized a home to steal food and her landlord threatened to evict the family, the affidavit said.

Mathis said she gave him drinking water and a “small portable toilet container” inside their home in the 10600 block of Northwest Second Place, police said.

The grandmother was taken into custody last week on charges of aggravated abuse of a disabled adult, abuse of a disabled adult and false imprisonment, the affidavit said. She also was charged with aggravated child abuse because the alleged abuse began when her grandson was underage, police said.

Mathis declined to comment Tuesday outside her home. A man that was with her said, “The child was never neglected. The truth will come out.”

Mathis’ grandson, whose name was not released, told officers that Mathis chained him to his bunk bed every night, police said. He was taken to University Hospital and Medical Center, where he remained Tuesday, police said.

When police visited the family’s home last month, Mathis was out of state and had left the boy at home in the care of a family friend, the affidavit said.

The young man told police that “he deserved to be chained to the bed” and that “it was for his own good,” the affidavit said. He said his confinement prevented him from committing burglaries for food, the affidavit said.

The man disliked it when officers questioned his relatives, police said. He grabbed a broken broomstick and tried to strike one officer, the affidavit said. Police confined him under the state’s Baker Act, a law that allows mental-health professionals and authorities to detain a person for up to 72 hours to determine their mental stability.

At the hospital on Jan. 1, he was involved in a disruption that required hospital staff members to subdue and restrain him, the affidavit said. During the incident, his right arm was broken, police said.

Though many families face challenges, “it’s never appropriate in any circumstance to chain your child to a bed,” said Mark Riordan, spokesman for the Florida Department of Children & Families.

Riordan said parents can phone 211 Broward, a help line that provides information and referrals for health and human services and crisis/suicide intervention. “There is a vast array of services,” he said.

DCF has since opened investigations pertaining to the young man, his 14-year-old brother and 15-year-old sister, officials said. His siblings also lived at the home and were in Mathis’ care for about 14 years, police said.

A police review showed the family had eight prior child protective services reports. Of those, six were associated with Mathis after the children were placed in her care. The other two reports were associated with the man’s mother, who lost custody of her children in 1996, police said.

Observing the man’s behavior, police said he might have a developmental disability, the affidavit said. Police did not elaborate, citing medical privacy laws. The man’s competency is under evaluation, Riordan said.

“This family was known to us, and we worked with them in the past,” Riordan said. “This is the first time that these allegations came to our attention.”

The man was locked in the bedroom with his younger brother at night even though his brother was not chained, police said.

The siblings were taken into DCF custody, Riordan said.

Mathis’ friend, as well as her fiancé, acknowledged they sometimes helped chain the young man, a police affidavit said. They are not facing charges after police determined they were acting at the instruction of Mathis, said McHugh, the police spokesman.

DCF urged anyone with information about children or vulnerable adults being abused to call the Florida Abuse Hotline at 800-962-2873.

Sun Sentinel staff researcher Barbara Hijek contributed to this report.