In late 2011, Destene Chardoney Simmons put a pillow over her 3-year-old son’s face and tried to suffocate him. Antwan Hope was taken from her care by the state, but returned to her last weekend for an unsupervised visit, their first since the removal.

He left the visit in a body bag.

Coral Springs police are investigating Antwan’s death Monday, a week after the 4-year-old had celebrated his graduation from preschool. The department has called the youngster’s death “suspicious.”

The boy’s distraught relatives said it was clear Antwan’s mom was disturbed and that she should not have had unsupervised access to him.

“They put him in the hands of death,” said Antwan’s aunt, Deborah Jackson.

Antwan’s body was discovered early Monday after police received “hang up” calls from Simmons’ home. Simmons spent Monday night at the Broward County Jail on unrelated charges of driving with a suspended license, and was expected to bail out from the jail sometime Tuesday. By late afternoon, television news trucks were camped outside the jail awaiting Simmons’ release.

At about 10 a.m. Tuesday, the Broward County Medical Examiner’s Office performed an autopsy on the child, said Coral Springs Lt. Joe McHugh, a department spokesman. Though the autopsy was completed by late Tuesday, the M.E.’s office was classifying Antwan’s death as “pending further investigation” and still could not identify what caused the death, McHugh added.

“My son was everything to me,” said 28-year-old Antwan Hope, the boy’s father. “I’ve been a father to my son, and now he’s gone.”

Antwan’s father was never given custody of Antwan, but he said he was given generous visitation and saw his little boy often. Antwan Hope, the father, lives in Deerfield Beach with his grandmother, and his little boy saw much of his extended family on visits.

Jackson, the aunt, described the little boy as “cute and innocent.” Antwan, relatives said, liked to dance and sing rap songs, and was becoming a very good Nintendo player. “He was a bright little boy,” Jackson said, “very lovable.”

But, she added, “he just needed to be rescued.”

Administrators at the Department of Children & Families, which oversaw the boy’s care through its contract with a private Broward foster care agency, declined to discuss Antwan’s death in detail Tuesday. Alexis Lambert, an agency spokeswoman in Tallahassee, said investigators took custody of Antwan in December 2011, and his child welfare case remained open at the time of his death.

“We take child deaths very seriously, and we take this case very seriously,” Lambert said. But because police and the Medical Examiner’s Office have yet to determine what killed the youngster, the agency is not at liberty to discuss his case. Under Florida law, DCF can only talk openly about children who died because of abuse or neglect. If police and medical examiners conclude Simmons is responsible for her son’s death, or if she is arrested in connection with the death, DCF will release agency records related to the child, Lambert added.

Antwan was taken from his mother’s custody last year after Simmons picked him up from school one day, drove him to a motel and smothered him with a pillow. Jackson, who is Antwan’s paternal aunt, said a friend of Simmons called police, who arrived in time to save the boy. Simmons was committed under Florida’s involuntary commitment law, the Baker Act, to a local psychiatric hospital, and Antwan was placed in foster care, and then in the home of a maternal aunt.