A Mount Laurel man pleaded guilty Tuesday to killing his wife on New Year's Eve last year and then dumping her body in a wooded area in Maryland, where it lay undetected for more than two months.

Kyle Crosby, 29, entered the plea to charges of aggravated manslaughter and hindering apprehension in Superior Court in Mount Holly and will be sentenced to 31 years in prison, the Burlington County Prosecutor's Office said.

Charges against his mother, Jo, 68, of Sicklerville, who authorities said helped her son conceal the crime, will be dismissed as part of the plea agreement.

Crosby admitted in court Tuesday that he choked Erica Crippen, 26, at their home. She was reported missing Jan. 7 after her daughter from a previous relationship, now 8, was not picked up from school. Crosby and Crippen had a 1-year-old daughter.

Barbara Kellam, Crippen's cousin, said that the plea and cause of death answered the family's questions, but that the pain lingers. Kellam said she had not put up a Christmas tree or lights because this time of year reminds her of Crippen's death.

"We're very depressed," said Kellam, 35, of Lindenwold. "Just trying to get through this holiday."

Authorities said Crosby disposed of Crippen's body in Sykesville, about 30 miles west of Baltimore, late Jan. 10 or early Jan. 11. He was arrested Jan. 12 in Bellmawr after a traffic stop.

Investigators found the body March 17, wrapped in a fleece blanket. The neck, hands, and feet were bound with yellow electrical wire, authorities said, and the mouth and nose were covered with duct tape.

The body was found after investigators combed through more than 8,600 locations on Crosby's GPS device. Authorities said Crosby marked two locations where he considered dumping Crippen's body, labeling one "Maybe" and the other "Idk" for "I don't know."

He also left a box of partly eaten chicken and a business card with an 856 area code next to Crippen's body, prosecutors said.

Jo Crosby was indicted in April, accused of hindering apprehension and tampering with or fabricating physical evidence. Prosecutors said she exchanged text messages with her son the night he killed Crippen.

"Please do not touch her in any way or form," Jo Crosby told her son in one message, according to an affidavit. Kyle Crosby "indicated that he was not that stupid," the affidavit said.

Crosby, who is held in the Burlington County Jail, will be sentenced Feb. 4.

mboren@phillynews.com 856-779-3829 @borenmc