Montville ― The father of an infant who suffered a life-threatening brain injury and other injuries faces first-degree assault and other charges stemming from a December 2022 incident at his Uncasville home.

Montville police charged Shane Siegrist, 34, of 19 Crescent St., on Monday with first-degree assault, reckless endangerment, risk of injury to a minor and cruelty to persons. He was held on a $150,000 bond. A court date was not available Wednesday evening.

According to the affidavit for his arrest warrant, Siegrist was caring for the 5-week-old boy during the evening of Dec. 19, when the boy’s mother and her stepmother went shopping. Siegrist’s two teenage stepsons were home at the time.

The warrant states the two teenagers and other adult witnesses all said the two teens did not handle or feed the infant.

After the mother returned home, the baby became semi-unresponsive, the parents told police and emergency responders. The baby was twitching at times, would open one eye and his face was drooping on one side. The parents initially called the baby’s doctor and were told to call 911.

An ambulance brought the baby to the Backus Hospital in Norwich, where a CT scan showed life-threatening injuries, including bleeding between the skull and the brain and retinal hemorrhages in both eyes “which is consistent with trauma,” according to the warrant.

The baby also had bruises on his front and back torso, both shoulders and one forearm. A Backus physician described the bruises as “consistent with a handprint,” the warrant states.

The warrant states that the bruises exactly matched Siegrist’s handprint.

The baby was flown by Life Star helicopter to the Connecticut Children’s Medical Center in Hartford where he underwent emergency brain surgery.

According to the warrant, the baby was released from the medical center on Jan. 10 to the custody of a family friend approved by the state Department of Children and Families.

“Despite the victim being released from the hospital and his ability to move his arms and legs, it was concluded that neurologic prognosis remains uncertain, and the victim is at high risk for disability following his injuries,” the warrant states.

Montville police Detective Brittany Noyes led the investigation, interviewing the parents, other family members, medical staff and reviewing footage from a video camera in the home’s dining room.

The baby had been placed in a crib/playpen in the living room on the evening of Dec. 19. Police said on the camera footage, the baby could be heard crying from 5:08 p.m. to 5:12 p.m., and Siegrist could be heard and seen at times entering the living room. Later, the camera showed Siegrist holding the baby walking from the living room to the kitchen.

Police reviewed the contents of Siegrist’s cellphone. Shortly after 10 p.m. an internet search was done on the phone for signs of “baby night terrors,” and for “newborn sleeping too much.” The baby’s mother told the 911 dispatcher that the baby had been sleeping for more than seven hours and could not be awakened.

Witnesses told police that Siegrist at various times had said he thought he might have swaddled the baby too hard and said, “I don’t know my own strength.” Asked by medical staff about the bruises on the baby’s legs, Siegrist allegedly said the baby sometimes “fusses” when he is being changed, and Siegrist had to grab his leg.

According to the warrant, when the baby’s doctor asked Siegrist how he thought the head injury occurred, Siegrist responded, “No idea. I don’t want to think about that.”

At the time of the incident, Siegrist was on probation for a previous conviction for risk of injury to a minor. A condition of probation was that he not have unsupervised contact with minors. A state probation officer told police the office was aware he was living with three minors at the time, and that the arrangement was approved, with the baby’s mother as the supervisor for all contact with the minors.

“However, the accused was not allowed to be alone with the children,” the warrant states.

c.bessette@theday.com