PORTLAND, Maine — A 34-year-old Westbrook woman faces felony charges of gross sexual assault after police say she allowed her boyfriend to sexually assault a 14-year-old developmentally delayed girl.

Holly A. Morrison was indicted by a Cumberland County grand jury on three class A counts of gross sexual assault, as well as three counts of endangering the welfare of a child.

The boyfriend, 59-year-old Donald Cass of Auburn, pleaded guilty in February to two counts of gross sexual assault and was sentenced to eight years in prison with all but four years suspended, and four years of probation, according to court documents.

According to affidavits by Westbrook police officers, the victim reported to friends and a Department of Health and Human Services worker on November 14 that the woman’s boyfriend had been sexually assaulting her since the beginning of October.

The victim is related to Morrison.

The victim told police that Cass used objects to sexually assault her, and said the woman assisted Cass by insisting she get into bed with the two of them and shower with them.

Police allege that Morrison admitted to seeing Cass assault the victim on three occasions.

Cass said “she did not approve of Donald Cass’ behavior, but she said at some point he had convinced her that this behavior was normal,” according to an affidavit.

Morrison allegedly told detectives that she met Cass at a “swingers’ party.” Cass visited her on weekends for five years, unbeknownst to his wife.

Morrison was indicted earlier this month. She was released on $500 bail. A court date was not immediately available.

To reach a sexual assault advocate, call the Statewide Sexual Assault Crisis and Support Line at 800-871-7741, TTY 888-458-5599. This free and confidential 24-hour service is accessible from anywhere in Maine. Calls are automatically routed to the closest sexual violence service provider.