Putnam (AP) — A 2-year-old boy who died last month apparently choked on cereal after his father’s girlfriend locked him and his 1-year-old brother in a bedroom while she went to a methadone clinic, state police said.

The girlfriend, Renee Peterson, 32, of Putnam, was arraigned Thursday in Danielson Superior Court on charges including cruelty to persons, risk of injury to a minor and reckless endangerment. She was held on $125,000 bail. Her public defender insisted she didn’t mean to harm the boy.

The father, David Mahan, 30, faces the same charges. He was arrested Wednesday in Douglas, Mass., and is expected to be extradited to Connecticut.

Peterson, who has two daughters, ages 6 and 4, told police that she routinely locked Mahan’s sons in their bedroom and left them alone for several hours a week, according to an arrest warrant affidavit. She also told authorities that Mahan told her to lock the boys in their room while she went to the methadone clinic, which Mahan denied, court documents say.

On March 26, she gave the boys bowls of dry cereal and locked them in their room while she and her younger daughter went to the clinic in Willimantic, police said. When she returned about two hours later, the 2-year-old was unresponsive and slumped over a table, police said. Peterson called 911, and a dispatcher instructed her on how to perform CPR on the boy, who was pronounced dead at Day Kimball Hospital, the affidavit said.

Peterson’s public defender, Claudia Jones, said she had no previous criminal history and was fighting a long-running drug addiction, the Norwich Bulletin reported.

“She placed herself in treatment, trying to maintain her sobriety,” Jones said. “There’s no question this is a sad case, an extremely awful, sad situation that was unintentional.”

Mahan told investigators that he knew Peterson was locking his children in their room but he didn’t agree with it, according to court documents. He said he had tried to arrange day care for his sons after recently getting a new job.