A fourth suspect wanted in connection with an ice-pick slaying of a pregnant woman near Tonasket turned himself into Spokane police on Sunday night, authorities said this morning. David E. Richards, 33, was being held in Spokane County Jail for Okanogan County sheriff’s deputies, who have taken into custody three other persons in the beating and stabbing of Michelle L. Kitterman, 25, of Tonasket. Richards was being held on a warrant charging him with first-degree murder and first-degree manslaughter with a $1 million bail. Kitterman was found dead on March 1 along a driveway adjacent to Stalder Road near Tonasket in Okanogan County. Kitterman was at least 11 weeks pregnant and allegedly had been involved in an affair with the husband of Lacey K. Hirst-Pavek, 33, of Tonasket, who was arrested at her parents’ home Tuesday night. Hirst-Pavek is accused of offering $500 for the killing, and renting a car that detectives said was used in the attack, authorities said. She was released last week from Okanogan County Jail on a $250,000 bail and is charged with conspiracy to commit first-degree murder and conspiracy to commit first-degree manslaughter, Okanogan County Sheriff Frank Rogers said. Also arrested last month was Tansy Fae Mathis, 29, formerly of Tonasket, who is believed to have met with Hirst-Pavek several times before reaching an agreement to “take care of” Kitterman for $500, Rogers said. Mathis is accused of getting Richards and a fourth suspect, Brent L. Phillips, 38, of Spokane, to become involved in the brutal confrontation of Kitterman. Richards is believed to have provided the ice pick, Rogers said. Phillips and Mathis, both arrested two weeks ago, were being held on $1 million bail in Okanogan County. Phillips has had several convictions for assault and was being held on charges of first-degree murder, first-degree manslaughter and evidence tampering. Mathis is charged with conspiracy to commit first-degree murder and conspiracy to commit first-degree manslaughter.