BRENTWOOD, N.H. – A New Hampshire woman has been sentenced to 15 to 30 years in prison after reaching a deal with prosecutors to plead guilty to conspiracy charges in the death of her husband’s ex-wife in 2013.

Sarah Desjardins of Epping was accused of being an accomplice to first-degree murder in the death of Amanda “Amy” Warf.

Desjardins, 35, was sentenced to 15-30 years in prison in Rockingham Superior Court on Friday. WMUR-TV reported that she pleaded guilty to conspiracy to commit murder and conspiracy to hindering apprehension.

Her husband, 38-year-old Aaron Desjardins, was sentenced in March to life in prison without the possibility of parole after pleading guilty to first-degree murder and conspiracy.

His sister, 44-year-old Michele Corson of Skowhegan, Maine, pleaded guilty to conspiracy charges. She is scheduled to be sentenced in September.

Prosecutors said Aaron Desjardins ambushed Warf in her employer’s parking lot in March 2013 and forced her to drive to a vacant concrete plant in Exeter, where he slit her throat, poured gasoline on her and set her ablaze. They said his plan to kill her dated back to 2011, when she left him.

Officials say Aaron Desjardins was upset over custody of their young son, William.

Warf’s mother, Nancy Warf, said she and her family opposed Desjardins’ plea deal. She addressed the court before Desjardins was sentenced.

“My daughter was sentenced to death by Sarah. William has been sentenced to a life without his mommy by Sarah. My family and I have been sentenced to life without Amy by Sarah,” Nancy Warf said.