ST. LOUIS – A man accused of supplying fentanyl to a St. Charles mother last month before her overdose death faces criminal charges.

Federal prosecutors have charged Valentino Carpenter, 37, of Maryland Heights, with possession and distribution of fentanyl in the investigation.

Officials did not identify the victim, but say she left behind three young children, ranging from 2 months old to 4 years old. According to court documents, the children had been alone in a bedroom for up to 20 hours after their mother’s death before their screaming alerted a neighbor.

Investigators say Carpenter sold two capsules containing suspected fentanyl for $10 and met the victim at her home on Lindenwood Avenue on the morning of June 21. Investigators believe Carpenter was aware that the woman’s children were in the home. About three hours later, investigators say Carpenter messaged the victim and told her not to ingest a whole capsule, adding “you almost died last night.”

A neighbor entered the home after hearing screams, then found the victim dead on her couch and children confined to the bedroom with a baby gate.

Police then responded to the scene, finding one black and white capsule which tested positive for fentanyl in a field test. Investigators later reviewed Facebook messages in which the victim told Carpenter she wanted to buy fentanyl. Authorities arrested Carpenter on July 7.

“While the facts in this case are appalling, it is just one of many currently being investigated by law enforcement in the St. Louis area, and every case seems more tragic than the next,” said U.S. Attorney Sayler Fleming Wednesday.

Relatives are now caring for the three children, according to the U.S. Department of Justice.

If convicted, Carpenter faces up to 20 years in prison and a fine of up to $1 million.