AUGUSTA — For the second time in three months, Richard M. Libby, 48, of Windsor, pleaded guilty to a series of sexual assaults on a young girl over an eight-year period.

On Monday, however, the court hearing ended with him being sentenced to 20 years in prison, with all but 13 years suspended and 16 years’ probation.

Justice Thomas Warren accepted Libby’s withdrawal of his prior guilty pleas and then took eight new guilty pleas after Libby acknowledged he was aware of his right to go to trial.

The state, through Deputy District Attorney Fernand LaRochelle, sought a sentence of 30 years, with all but 20 years suspended and 16 years’ probation for the sexual offenses that began when the girl was 6 and continued until she was 14. According to the indictment, the offenses began in August 2002 and continued through August 2009 and took place in the girl’s home in Windsor.

Libby’s defense attorney, William Baghdoyan, suggested a sentence of 14 years in prison with all but seven years suspended and 12 years’ probation.

At Monday’s hearing in Kennebec County Superior Court, Libby read aloud three letters he had written to apologize for his actions and said he does not know why he did it. The letters were addressed to the court, the victim’s mother and the victim herself.

“It’s my fault this crime happened,” Libby said. “I couldn’t control myself.” He said he was overwhelmed by a number of mostly bad things happening in his life. “I wasn’t thinking straight. I was only thinking of my own wants and needs. There’s no excuse for what I’ve done. To the victim and her mother. I want to express my sincere apologies for what I’ve done.”

His statements were punctuated by his wiping his eyes and sniffling. Most of the time he kept his head lowered.

“I’m ashamed of myself for what I’ve done,” Libby said twice. “I can’t stand to look at myself in the mirror because I hate who I see.”

In contrast to December, when Libby previously pleaded guilty to eight similar charges, this time the victim’s mother was absent from the courtroom. Instead she and the victim were represented by the victim/witness advocate in the Kennebec County District Attorney’s Office.

After Libby’s hearing in December, the mother of the victim left the courtroom in tears.

Warren said he decided that society needs to be protected after he heard Libby’s statement that he couldn’t stop even when he knew it was wrong.

Part of that factored in fashioning the lengthy period of probation. Libby pleaded guilty to four counts each of gross sexual assault and unlawful sexual contact.

Warren said the effects of the crimes on the victim were extremely significant, and cited from her impact statement.

“She’s referring to her childhood as ‘continuous torture’ and talking about the fear and shame that went on for years and years,” Warren said.

Conditions of probation ban Libby from contact with the victim and her mother and from any girls under age 16.

Libby also must register as a lifetime registrant on the state’s sex offender registry.

Betty Adams — 621-5631badams@centralmaine.comTwitter: @betadams