AUBURN — A Lewiston man Friday denied causing the death of his nearly 1-year-old son, who was left without supervision in a bathtub last month.

Sean St. Amand, 27, was indicted by an Androscoggin County grand jury this week on charges of manslaughter and endangering the welfare of a child.

The grand jury charged that St. Amand “did recklessly or with criminal negligence” cause the death of his son, Sean Jr. That charge carries a penalty of up to 30 years in prison. The second charge is punishable by up to 364 days in jail.

St. Amand appeared in Androscoggin County Superior Court on Friday and pleaded not guilty to the two charges. He has been held at Androscoggin County Jail.

A judge Friday set bail at $2,500 plus a contract for supervision. During that time, he would be barred from having unsupervised contact with the two children at his home.

He also would be prohibited from having alcohol or illegal drugs and would be subject to random search and testing for them.

Police said St. Amand on Oct. 20 placed his son in a bathtub with the boy’s sister, Shay-Lynn. The father left them for an undetermined length of time. When he returned, the boy was unresponsive. He was taken by ambulance to Central Maine Medical Center where he was pronounced dead. Shay-Lynn St. Amand was nearly 2 years old at the time of the incident.

Police said the incident took place at 125 Pierce St. The boy’s mother, Jennifer Everett, 28, was taking a nap in the apartment at the time.

Police did not know why the father left the room or how long he was gone.

A check of St. Amand’s criminal record showed several misdemeanor crimes in 2011: criminal trespassing, theft by unauthorized taking, refusal to submit to arrest or detention and violation of the conditions of his release.

The baby’s death continues to be investigated.

An autopsy by the State Medical Examiner’s Office found the baby died from drowning. It found no drugs in his system.

This story was updated Jan. 8, 2015 to include the autopsy results.

cwilliams@sunjournal.com