BRENTWOOD, N.H. — A New Hampshire man who once said he had nothing to do with his ex-wife’s death is planning to enter a guilty plea in the case.

Aaron Desjardins of Epping is charged with first-degree murder in the March 2013 killing of Amanda Warf. His sister, Michele Corson, of Skowhegan, Maine, who faces accomplice to first-degree murder and other charges, also plans to enter a guilty plea.

Prosecutors say Desjardins slit Warf’s throat and set her body on fire in a vacant concrete plant in Exeter to try to cover up the evidence.

The notices to plead guilty don’t specify a charge.

In an affidavit unsealed this year, the 37-year-old Desjardins said Warf was trying to take away their son and he plotted with his current wife, Sarah Desjardins, to kill Warf.

Sarah Desjardins also is charged as an accomplice.