An Irish Army private — who resigned last Friday after 15 years service — has been put behind bars for two years and three months for sex assaults on a 13-year-old girl.

Judge Ray Fullam imposed three years in jail on 34-year-old father of three Kenneth McDonald, but suspended nine months of the sentence at Donegal Circuit Court.

McDonald of Ernedale Heights, Ballyshannon, has also been placed on the sex offenders register. He was convicted by a jury of four counts of sexual assault on the girl on dates between June 1 and November 30 2003. The offences occurred in his car near woodlands in south Donegal.

Judge Fullam said McDonald, who was 28 at the time, had taken advantage of the girl when she was legally incapable of consenting to sex because of her age. McDonald also knew at the time that she was effectively abandoned, without guidance and was “beginning on a life of promiscuity”. He added to her “degradation” for his own self-gratification.

The girl, who is now 19, told the trial earlier this month that she had full sex 57 times with 22 adult men when she was 13. She kept a diary of her encounters and a “period chart” to help her identify the father if she became pregnant. The court heard that there are to be five other prosecutions. Judge Fullam was also told yesterday that initially gardai were concerned that there was a child-sex ring in operation in the area, but this proved to be untrue.

Judge Fullam paid tribute to gardai who looked after the girl during five years she was in care after the inquiry started in November 2003.

The judge said that from the girl’s demeanour in court, he recognised she was a different person to what she was six years ago.

The court heard that McDonald’s wife Maggie is standing by him. She was in court as were other members of his family. His victim was accompanied by a social worker. There was nobody from her family there.

During the two-hour sentencing hearing, part of a victim impact report from the girl was read by prosecuting counsel Eileen O’Leary, SC.

The report stated that the girl said that shortly after she was taken into care in December 2003 following the start of a Garda investigation, she began taking drugs regularly to “block out the trauma”. She absconded a number of times and was rebellious.

She said: “I missed my family and wanted and longed to be with them all the time. I started self-harming and cut my arms and legs. I overdosed a number of times.”

Garda Feeney told defence counsel Cormac O’Dulachain that at one stage during the investigation there was concern that a child-sex ring was operating in the area but that was found not to be true in any way.

At one stage of the investigation, when McDonald went through a period of bad depression, firearms were taken with the co-operation of the Army from his house “for his own safety”.

Judge Fullam heard that when McDonald joined the Army he was following a family tradition as his father had also been a serving soldier. McDonald was based throughout his career at Finner Camp, a few kilometres from his home.

McDonald winked at his wife and she raised her hand in acknowledgement as he was led away.