PEABODY — A Beverly man will serve no more than 31âÑ2 years in state prison for repeated sexual assaults on a young Peabody boy, a Salem Superior Court judge decided yesterday.

Prosecutors had sought at least a six- to eight-year prison term for Shawn Finnegan, 31, describing how Finnegan abused the boy for two years, when he was between the ages of 6 and 8.

Finnegan was living in Newburyport, on Prospect Street, for most of that time. He later moved to Bridge Street in Beverly, where he lived at the time of his arrest.

"These were despicable, horrific and unimaginable acts committed by a person in a position of trust," prosecutor John Brennan told Salem Superior Court Judge Timothy Feeley yesterday.

Brennan said the boy, now 11, "has been scarred brutally by the defendant and will have to live with these scars the rest of his life."

But Feeley said that while Brennan's recommended sentence for child rape and two counts of indecent assault and battery was reasonable, Finnegan's lack of a prior record and "the strong value and interest in not having the youngster have to appear in court" led him to a lower sentence of 21âÑ2 to 31âÑ2 years.

The boy appeared briefly at the courthouse yesterday morning to attend the sentencing but was brought home by a family member because he was not feeling well.

Defense lawyer Jennifer Koiles, who had urged even less time, two years in prison, said her client was "taking responsibility for his actions and not forcing the child to go through a trial."

Brennan said that the abuse came to light while the boy was riding home from a baseball game in June of 2006.

The boy told his father that Finnegan had touched his groin.

But Finnegan had done much more than that, the boy would eventually disclose, repeatedly raping the boy and touching him inappropriately.

Finnegan, who worked as a mortgage broker, was a clean-cut professional who had befriended the boy's older sister and then the boy's troubled family, posing as a mentor to the child. He began inviting the boy to spend nights at his Newburyport apartment, Brennan said. During those increasingly frequent visits, Finnegan would molest the boy.

After Brennan read the allegations, Feeley asked Finnegan if they were true.

In a barely audible whisper, his voice shaking, Finnegan answered. "Yes, your honor."

In addition to the six- to eight-year prison term, Brennan asked for five years of probation afterward, "although no amount of time is commensurate with what this defendant has done."

Feeley imposed a shorter probation term of three years for both of the indecent assault and battery counts.

Because the crimes occurred before the law requiring sex offenders to wear GPS tracking bracelets was in effect, Feeley did not order Finnegan to wear such a device when he is released from prison.

He did order Finnegan to have no unsupervised contact with any child under 16 except for his own child. He is also barred from any contact with the victim or the victim's family.

Finnegan will have to register as a sex offender, take part in sex offender counseling, and submit a DNA sample to a state database.