BRIGHTON, Colo. (KDVR) – Police in Colorado have arrested two people following the death of their 23-month-old daughter, whose blood was found to contain 10 times the amount of fentanyl known to be fatal to an intolerant adult user.

Officials with the Brighton Police Department said they were called to a home in early January when Alonzo Ray Montoya, 31, and Nicole Danielle Casias, 30, reportedly found their child not breathing and unresponsive.

Several local agencies, including fire, EMS and police officials, attempted to perform life-saving measures to save the toddler. She was ultimately pronounced dead.

Detectives from BPD and the North Metro Drug Task Force began an investigation into her death in January. It was determined that her death was caused by fentanyl ingestion.

Earlier this week, the 17th Judicial District Attorney’s Office in Colorado announced that felony charges had been filed against Montoya and Casias: child abuse resulting in death and distribution of a controlled substance — schedule I or II.

Nicole Casis and Alonzo Montoya have been charged with child abuse resulting in death, and distribution of a controlled substance — schedule I or II. (Brighton Police Department)

In a news release, the DA’s office said the parents allegedly participated in drug activity in their home, with the toddler present, prior to her death.

Casias and Montoya were taken into custody on Wednesday. They are scheduled to appear in Adams County court on Thursday.