An Arizona couple has been charged with murder and child abuse after admitting to keeping their 6-year-old son and his brother inside a closet for a month as punishment for “stealing food,” authorities said.

Anthony Jose Archibeque-Martinez, 23, and Elizabeth Archibeque-Martinez, 26, have been charged with first-degree felony homicide and two counts each of child abuse after authorities found the 6-year-old boy dead in their home Monday, the Flagstaff Police Department told The Daily Beast. The child’s 50-year-old grandmother, Ann Marie Martinez, has also been charged with homicide and child abuse in the death.

“Both [parents] admit that the two boys were kept in the closet because they were stealing food, by sneaking out at night when the parents slept,” authorities said in a statement.

Authorities said that they responded to the couple’s home after receiving reports of “an unresponsive 6-year-old male child.” The boy did not show any immediate signs of trauma but appeared to be “malnourished” and his physical appearance “did not compliment his age.”

Despite several life-saving attempts, he was pronounced dead at the scene, police said. It was not immediately known how the 6-year-old died, authorities said, but the medical examiner is expected to make a determination within the week.

All three family members later admitted to authorities that the 6-year-old child and his 7-year-old brother were “kept in a bedroom closet and denied food at times” over the last month and were not let outside of their Flagstaff home. Authorities said the older son also appeared malnourished.

“During questioning of the grandmother, she admitted she was aware of this condition the boys were kept in and admitted to disciplining the children when they stole food,” authorities said.

Immediately after the interview, the Department of Child Safety took custody of the couple’s three surviving children, including a 4-year-old girl who regularly attended school and a 2-year-old. Neither children appeared to be malnourished, and the 7-year-old boy is currently being hospitalized at Flagstaff Medical Center, authorities said.

“We can confirm the child’s siblings are currently in DCS care and are receiving the care and services necessary to help them during this difficult time,” a Department of Child Safety spokesperson said in a Wednesday statement, adding the organization “mourns the tragic loss of this innocent life.”

The Department of Child Safety confirmed to The Daily Beast that agency workers had previously been called to the home on Feb. 18, 2013, after receiving a report of “two allegations of abuse” involving one of the 6-year-old boy’s siblings.

While “both allegations were unsubstantiated,” the department said in a statement that the Martinez couple “agreed to participate in voluntary in-home services,” which were completed in July 2013, at which point the case was closed. The couple and the child’s grandmother are currently being held in Coconino County Jail, according to jail records.

“Keeping children safe is the Department’s top priority. However, DCS cannot investigate child abuse and neglect unless we receive a report from the community,” the department spokesperson added.

A Flagstaff Police Department spokesperson declined Wednesday to provide details on the investigation, but stated deputies are interviewing family members, neighbors, and any possible witnesses to determine if anyone knew about the abuse.