A Washington woman is accused of plotting to kill her mother before stabbing her to death at a forest preserve in McLean County, according to prosecutors.

Christine E. Roush, 22, of Washington and Matthew Isbell, 20, of Marquette Heights were charged Saturday in McLean County Court with two counts of murder in the death of Teresa A. Poehlman, according to a news release from the McLean County State’s Attorney’s Office.

The body of Poehlman, a 47-year-old East Peoria woman, was found July 2 by a pair of hikers at a Funk's Grove nature preserve a few miles southwest of Bloomington.

Poehlman came to Bloomington to visit Roush, her biological daughter. She was staying in a motel with Roush and Isbell before her murder, according to the release.

Isbell came to the McClean County Sheriff's Office on Friday and provided officers with a timeline of the murder. He said Roush plotted to kill her mother and then stabbed her to death at the Funk's Grove preserve. Blood was found in the passenger seat of Isbell's truck, according to the release.

Roush initially denied involvement in Poehlman's death, but she was later arrested Friday after Isbell spoke with officers and provided information on her alleged involvement.

In his interview, Isbell also told officers of a third person involved in the killing, according to the release. Police continue to search for the suspect, who has been confirmed by Roush on a surveillance video.