Joliet, Ill. ? Authorities probing the disappearance of a police officer’s wife said Friday he is now considered a suspect in a potential homicide investigation, and that the death of an ex-wife three years ago appeared to have been staged as an accidental drowning.

Authorities received court approval to exhume the body of an ex-wife of Bolingbrook Sgt. Drew Peterson as they continued the search for his wife, Stacy, who was last seen Oct. 28.

Illinois State Police Capt. Carl Dobrich said Peterson, 53, has moved from being a person of interest in the disappearance of his 23-year-old wife to “clearly being a suspect.” Dobrich also said the case was now a potential homicide investigation.

“We have mixed emotions right now,” said Pamela Bosco, Stacy Peterson’s adoptive stepmother. “We’re sad, but we needed to move on, and this is something we’ve needed to hear for a long time.”

Drew Peterson has said Stacy Peterson phoned him and told him she had left him, and Peterson believed it was for another man. His attorney, Fred Morelli, did not immediately return calls seeking comment.

The family of Stacy Peterson, who was studying nursing at a nearby junior college, has said she feared her husband, was making plans to divorce him and would not have willingly left her children, ages 2 and 4.

The body of Peterson’s third wife, Kathleen Savio, was found in the bathtub in 2004, her hair soaked in blood from a head wound. A coroner’s jury ruled the 40-year-old’s death was an accidental drowning, even though there was no water in the bathtub. Investigators had theorized the water had drained out.

In a petition filed Friday listing the reasons authorities want to exhume Savio’s body, prosecutors said a review of evidence in the case “is consistent with the ‘staging’ of an accident to conceal a homicide.”