An Adams County jury convicted a Brighton man of five charges in connection to the fentanyl poisoning and death of his two-year-old daughter after he left her unattended for 14 hours. 

Alonzo Montoya, 33, was convicted of the following charges following a two-week trial that began on Jan. 8, according to a news release from the 17th Judicial District Attorney’s office:

• Colorado Organized Crime Act (COCCA) -racketeering
• Colorado Organized Crime Act – conspiracy
• Child abuse – recklessly causing death
• Child abuse – manufacture of a controlled substance (2 counts)
• Child abuse – knowingly/recklessly causes injury

An Adams County grand jury indicted Montoya of the multiple charges on Sept. 22, 2022 in connection to the child’s death.

On Dec. 11, 2022 Chief Judge Don Quick of the 17th Judicial District dropped the first-degree murder charges against Montoya and the daughter’s mother, 32-year-old Nicole Casias, ruling that the evidence did not support the parents “knowingly caused the death” of their 22-month-old baby, Aviyana Ramona Montoya.

Later investigations by the Brighton Police Department and the North Metro Task Force revealed that Alonzo Montoya was running a “large-scale” drug-dealing operation out of his home.

The incident occurred on Jan. 2, 2022. Police officers were called to the family’s home because the daughter was unresponsive and not breathing, according to a previous arrest record. The child later died.

The coroner determined that Aviyana had “10 times the amount of fentanyl in her system needed to kill an intolerant adult user,” according to the news release.

Evidence showed “that the defendants were using and selling fentanyl out of the family home for at least six months prior to their child Aviyana’s death,” a December 2022 court order said. “The post-autopsy testing of Aviyana’s hair follicles showed that she was subject to extended exposure (3 months) to the smoking of cocaine, meth and marijuana prior to her death.”

Surveillance video showed that Casias put the child in her crib for 14 hours, where she, at times, cried in pain due to teething. The video showed that Casias said, “Get out of that,” picked up Aviyana and put her in her crib, according to the warrant. It’s unclear what Casias was talking about in the footage, the previous indictment pointed out.

Aviyana had been seen placing objects around the room in her mouth in the footage, according to the release. Drugs and drug users were present in the room throughout intervals during the evening of the death.

Montoya will be sentenced by an Adams County judge on April 4.

Charges are still pending against Casias. Her case is scheduled to begin trial on March 11. 

“This defendant ran a large-scale drug operation while two children were present and now one of them is dead,” District Attorney Brian Mason said in the release. “This helpless child — who was teething at the time of her death — ingested fentanyl, which the defendant was selling, and had prolonged exposure to methamphetamines and other dangerous narcotics. It is one of the most outrageous cases I have seen.”