Human remains found buried on a property in Freeport have been positively identified as those of Jason Christopher Coulthart, a 43-year-old Niceville man who was reported missing on May 24, authorities said Thursday.

• Coulthart was last seen leaving the College Condominiums on East College Boulevard in Niceville. His disappearance prompted a missing person investigation by the Niceville Police Department, which on June 25 led detectives to a property off Sunset Lane in Freeport where they believed Coulthart’s body had been buried.

Because the property falls within Walton County’s jurisdiction, Niceville police notified the Walton County Sheriff’s Office, which obtained a search warrant that same day. Investigators found Coulthart’s body in a shallow grave that evening. The District 1 Medical Examiner’s Office responded to assist.

On Thursday, both agencies received DNA confirmation that the remains belong to Coulthart.

“This is not the news we hoped to deliver to our Niceville community,” Niceville Chief of Police Mark Hayse said. “We stand with Jason’s family and will continue working closely with our partners to see this case through.”

A homicide investigation remains active in Walton County. Three arrests have been made so far, and additional arrests are expected, according to the sheriff’s office.

Authorities are continuing efforts to locate Isabelle Johnson, 38, who is wanted on an open count of murder and is believed to be actively evading law enforcement.

• Johnson is described as a white female, approximately 5 feet 3 inches tall and 120 pounds, with brown hair and hazel eyes. She is known to use multiple identities and several aliases, including Harley, Jessica Elaine Bowman, Jessica Elaine Thrush, Jessica Dowdy and others.

“The next step in this investigation is to hold every single person involved in Jason’s death accountable,” Sheriff Michael Adkinson said. “If they knew, if they helped, or if they chose not to speak up, they will have to answer for their role in this.”

If Johnson is spotted, authorities say to not approach her. Call 911 immediately.

Anyone with information on Johnson’s whereabouts is asked to contact the Walton County Sheriff’s Office at 850-892-8111. Anonymous tips may be submitted through Emerald Coast Crime Stoppers at 850-863-TIPS (8477). A cash reward may be available for information leading to her location and arrest when submitted through Crime Stoppers.