A suspected serial killer currently in custody for allegedly killing two people in Pennsylvania pleaded guilty, on Wednesday, to murdering a Michigan woman in 2005, according to reports.

Fox station WXMI in Grand Rapids, Michigan, reported that Harold David Haulman III, 44, of Frackville, Pennsylvania confessed to killing Ashley Parlier of Battle Creek, Michigan on Wednesday morning.

Harold David Haulman III mugshot

A Pennsylvania man admitted on Wednesday to murdering a Michigan woman in 2005. (Pennsylvania Department of Corrections)

Parlier went missing in 2005, and at the time, she was pregnant.

Parlier’s family said she left home after an argument with her parents. She has not been seen since and her remains haven't been found.

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On Wednesday, Haulman reportedly admitted to knocking Parlier unconscious and transporting her to a remote area where he killed her with a piece of wood.

Police Caution Tape Crime Scene

FILE- Police caution tape at a crime scene. (iStock)

Parlier’s body is believed to be in Newton Township, just south of Battle Creek, though even with Haulman's help, detectives have not been able to find her remains.

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In Pennsylvania, Haulman confessed to killing two women, Tianna Phillips in 2018 and Erica Schultz in 2020.

When police interviewed him about those cases last winter, he also confessed to killing Parlier and said where he body might be found.

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Haulman was sentenced to life in prison for the murders of the two Pennsylvania women, and will ultimately be returned to Pennsylvania after a preliminary exam in Michigan in February.