BILOXI, Miss. (AP) — Charges have been upgraded against the parents of a 2-year-old who died last month at a Mississippi hospital, authorities said.

Joseph David Heard, 38, and Hailey Leann Heard, 21, of Biloxi, the child’s stepfather and mother, were arrested Wednesday on felony child abuse charges. The charges were upgraded Thursday to capital murder.

“The upgraded charges are the result of a collaborative investigation conducted by several local and state agencies,” police said in a press release.

The case stems from a Dec. 27 incident. Investigators said the woman called for help around 6 a.m. after she found her son unresponsive. First responders arrived and took the boy to a hospital where he was pronounced dead, news outlets reported.

The parents said the child stopped breathing and Joseph Heard conducted CPR. However, a police arrest report detailed the child had multiple bruises on his body and a broken bone consistent with abuse, which makes the death capital murder, WLOX-TV reported.

Both suspects are being held at the Harrison County Jail. Bond has not been set. It was unknown if either of them had an attorney who could speak for them.

Harrison County Coroner Brian Switzer said an autopsy will be conducted.