BOSTON — Months after the mother of a former inmate at Massachusetts Correctional Institute in Cedar Junction pleaded guilty to conspiring to distribute suboxone and alprazolam in the prison, prosecutors secured a guilty plea from the ex-wife of the former inmate, too, according to the U.S. Attorney’s Office.

The ex-wife, Lisa Guillemette, 42, pleaded guilty to the same charge in Federal Court in Boston, the U.S. Attorney’s Office for the District of Massachusetts announced Tuesday.

Guillemette is scheduled to be sentenced by U.S. District Court Judge Indira Talwani on Aug. 22, 2019.

The arrest comes after prosecutors discovered an apparent scheme to smuggle the substances into the Walpole prison that involved a prison nurse who alleged to have had a romantic affair with an inmate and a Fall River family.

According to charging documents, Guillemette’s ex-husband, William Guillemette, 39, directed his mother, and Guillemette to send the controlled substances to a P.O. box that the prison nurse, Christine Ramos, opened through a third party.

Ramos was alleged to be romantically involved with an inmate Chad Connors, 42.

Connors was sentenced to serve a minimum of 15 years in prison after being found guilty of second-degree murder in the Aug. 12, 2014 fatal beating of 72-year-old William Sires at the Souza-Baranowski Correctional Center.

Ramos agreed to smuggle contraband, including controlled the schedule III and schedule IV controlled substances, into MCI-CJ at Guillemette’s direction, according to charging documents.

Connors sent letters and money to Ramos at the two P.O. Boxes. William Guillemette asked his then wife, Lisa Guillemette, and mother, Margaret Guillemette, to send the opioid suboxone and alprazolam to the P.O. boxes.

From there, Ramos smuggled the drugs into the Departmental Disciplinary Unit, the unit where inmates are afforded limited time outside of their cell, according to charging documents.

Connors and William Guillemette distributed the drugs to other inmates and sent payment back to Lisa and Margaret Guillemette.

William Guillemette was serving a prison sentence up to 15 years after pleading guilty in 2009 to wounding his brother’s girlfriend with birdshot after an argument.

William and Margaret Guillemette previously pleaded guilty and are awaiting sentencing. Ramos was sentenced in April 2019 to two years of probation after pleading guilty to one count of conspiracy to distribute suboxone and alprazolam.