Brian Clark, 22, was sentenced Thursday in New London Superior Court to 10 years in prison for sexually assaulting a 23-month-old boy he was baby-sitting in July 2011.

Clark, of Norwich, will be on the state's strictest form of probation for an additional decade after his release and will be required to register as a sexual offender.

"It is a substantial sentence," prosecutor Theresa Anne Ferryman said in the courtroom. "The victim's mother has indicated she is not satisfied. I'm not sure any sentence would satisfy her."

The child's mother took him to the hospital in July 2011, saying he was in notable pain and had what appeared to be blood in his diaper. Clark admitted sexually assaulting the boy with his finger because he "wanted to see how it would feel."

Clark, who is represented by attorney Peter E. Scillieri from the public defender's office, has remained in prison while his case was pending. In November, he accepted the state's offer to plead guilty to risk of injury to a minor in exchange for a sentence of 20 years, suspended after 10 years served, followed by 10 years probation.

The state would have faced some challenges had the case gone to trial, since the victim is too young to testify, Ferryman said. While Clark did make a partial confession, laboratory tests of forensic evidence were inconclusive, Ferryman said.

Clark, heavyset in tan prison scrubs with close-cut blond hair, stood in silence as Scillieri spoke on his behalf. Clark was anxious and feared he would not be able to "get it out" if he tried to speak, Scillieri said.

"Mr. Clark has expressed remorse, which is both appropriate and encouraging," Scillieri said. "He admits he needs help and wants help."

Calling it a "distasteful" case, Judge Susan B. Handy said she hopes the victim was too young to remember the crime and that his mother can also move on now that Clark has been sentenced.

The judge told Clark that he had been put in a position of trust where he was expected to protect the child. Instead, she said, he perpetrated a very serious crime on the boy. While on probation, Clark will be required to attend sex offender treatment. Most aspects of his life, including where he lives and works and with whom he associates, will be monitored. He is prohibited from having unsupervised contact with minors.