Okanogan County sheriff's detectives have accused a Tonasket woman of having her husband's pregnant lover stabbed to death with an ice pick.

The sheriff's office says 33-year-old Lacy K. Hirst-Pavek was arrested Tuesday night and jailed for investigation of murder and manslaughter in the slaying of 25-year-old Michelle Kitterman. Her body was found March 1 in a Tonasket driveway.

The sheriff's office said Wednesday that Hirst-Pavek's husband was having an affair with Kitterman and Hirst-Pavek gave Tansy Fae Mathis $500 and the use of a rental car for the killing.

The 29-year-old Mathis and 38-year-old Brent L. Phillips were arrested last week. Detectives are looking for a fourth suspect, 33-year-old David Eugene Richards of Spokane.