AUGUSTA — A Vassalboro man employed by a social services agency to aid a woman with mental disabilities pleaded guilty Tuesday to sexually assaulting her.

Marshall L. Cox, 50, of Vassalboro, was sentenced to five years in jail with all but nine months suspended and six years of probation. He was ordered to register for 25 years under the state’s Sex Offender Registration and Notification Act.

Assistant District Attorney Kristin Murray-James told Justice Donald Marden in Kennebec County Superior Court that the gross sexual assault occurred on Thanksgiving 2013 after Cox had driven the woman to Bangor to have dinner with friends and then returned to her Augusta residence.

Murray-James said the sexual intercourse was consensual, and the defendant told the victim, who was receiving state-funded services for her diagnoses of mental retardation, bipolar disorder and post-traumatic stress disorder, not to tell anyone.

Cox initially denied having intercourse with her, but then told an investigator that he had done it.

“He said he made a bad decision,” Murray-James said.

Defense attorney Pam Ames said because Cox worked for a state-funded program providing services to her, it was illegal for him to have sex with her.

Probation conditions ban him from contact with the victim, now 26.

At a separate hearing, Sidney W. Williamson, 56, of Fairfield, pleaded guilty to two counts of unlawful sexual contact that occurred between Jan. 1, 2010, and Dec. 31, 2011, in China. The victim, a girl age 6 and 7 at the times of the respective offenses, later described the events to a school counselor, according to Murray-James

Williamson denied having any sexual contact with the girl.

“My client still indicates he did not do his offense,” Ames said on Tuesday. However, both Ames and Williamson told the judge that Williamson could be convicted if a jury believed the girl and that the plea was in Williamson’s best interests.

Williamson was sentenced to 10 years in prison with all but 42 months suspended and 12 years of probation.

Williamson was ordered to register again as a lifetime sex offender. He has been on the registry already as a result of 1988 convictions for rape and unlawful sexual contact.

Williamson told the judge he hasn’t touched alcohol or marijuana for about the past two years and has been highly involved in studying the Bible.

“I’ve learned all the wrongs I’ve been doing all these years,” Williamson said.

The victim’s parents watched the hearing from seats in the back of the courtroom but declined to address the judge in court. Conditions of probation prohibit Williamson from having contact with the victim and from unsupervised contact with girls under 16.

Betty Adams — 621-5631

[email protected]

Twitter: @betadams

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