Police have unearthed the remains of two people and believe up to three more are buried in a cornfield near the boyhood home of a man charged with murder in one of the deaths.

Guided by tips and anonymous letters, authorities Tuesday combed 220 acres near Highland, about 30 miles from St. Joseph, Mo., for more bodies.Hunters on Sunday came across a skull and bones in the field, and officers on Monday unearthed a body.

The skeletal remains have not been identified, but the body was identified Tuesday as that of Crystal Simmons, 33, who vanished from St. Joseph on Oct. 29. An autopsy showed she died of blows to the head, investigators said.

Marvin Irvin, 41, was charged Thursday with murdering Simmons. He was one of the last people seen with her, and blood was found in his truck, authorities said.