AUGUSTA — A former teacher at Monmouth Academy was sentenced to serve nine months behind bars, and placed on probation for three years, for having a sexual relationship this summer with a girl who was his student.

Christopher I. Dumaine, 39, of Readfield pleaded guilty today in Kennebec County Superior Court to two counts each of gross sexual assault and unlawful sexual contact and one count of violating a condition of release.

He was sentenced to four years in jail, with all but the initial nine months.

He resigned Sept. 17 from Monmouth Academy after teaching there for 16 years.

The victim, a 16-year-old girl, sat with her family in the back of the courtroom during the sentencing hearing in Kennebec County Superior Court.

She watched Dumaine constantly and, in a letter to the judge, asked the judge to allow her to have contact with Dumaine once she turns 18.

Conditions of probation bar Dumaine from contact with the girl, her family and Monmouth Academy, and from having contact with girls younger than 18 unless they are his children or unless he is supervised by a person approved by his probation officer.