A Michigan man pleaded guilty Wednesday to second-degree murder in the death of his girlfriend in 2001.

Gerard Dunston, 48, entered into a plea agreement with prosecutors that calls for him to receive 15 to 20 years in prison for the crime. He will be sentenced in August.

Dunston was living with Germaine Jones on Commerce Avenue in Chesapeake when she disappeared in May 2001. Her skeletal remains were discovered in a wooded portion of Bennett’s Creek Park in Suffolk on Nov. 15, 2001. A medical examiner determined that she had died of a blunt-force injury to her head.

The case was investigated at the time, but closed without being able to charge a suspect.

In January 2003, the cold case was assigned to Detective John Jones of the Suffolk Police Department. He investigated the case off and on for six years, before finally being able to charge Dunston in August 2009. Dunston was then arrested in Kalamazoo, Mich.

Dunston’s jury trial initially was scheduled for May 5, but he changed his plea on Wednesday.