Boone County double homicide suspect found dead in South Dakota

The man authorities believe killed a Boone County woman and her daughter last month was found dead from a self-inflicted gunshot wound Wednesday night in South Dakota.

JT McLean, 45, of Fulton, was accused of killing Allison Abitz, 43, and her daughter, Jozee, 11, on Aug. 22 at their home south of Columbia on Lavender Drive.

"We do not have things like this happen very often. We have three families that were heavily impacted," said Capt. Brian Leer of the Boone County Sheriff's Office. 

McLean likely was in the mid-Missouri region within the past week, Leer said. The department is still working to confirm McLean's movements the past three weeks.

More: Double homicide suspect likely attempting to disappear, authorities say

McLean was also accused of killing two people in Miller County whose bodies were found Wednesday, according to the Miller County Sheriff's Office. The two Miller County victims were identified as Daniel Stephan, 74, and Pamela Stephan, 64.

The two Miller County victims were related to an ex-wife of McLean.

The Boone County Sheriff's Office on Wednesday revealed that McLean was in possession of a dark-colored motorcycle that was not registered to him. Authorities believe McLean used the motorcycle to travel to Miller County.

The motorcycle was found in the woods near the home of the Miller County victims.  McLean is believed to have stolen a vehicle from one of the victims to flee the state.

Authorities tracked the vehicle, through the help of OnStar, to a motel parking lot in the Dakota Dunes area, the Union County, South Dakota, Sheriff's Office reported.

Relatives of the Miller County victims were known to have family in this area of South Dakota, neighboring Sioux City, Iowa. Authorities there contacted the family to move them to a safe location.

Authorities found McLean dead in his vehicle in the motel parking lot.

The Union County Sheriff's Office was assisted by the U.S. Marshal's office of Sioux City, Iowa, South Dakota Department of Criminal Investigation, South Dakota Highway Patrol, Sioux City Police Department and North Sioux City Police Department.

More: Cause of deaths revealed in Columbia double homicide as search continues for suspect

Allison and Jozee Abitz were found dead in their home Aug. 22 by the Boone County Sheriff's Office after a wellness check was requested by family members.

McLean was Allison Abitz's long-term boyfriend. 

Authorities found reason to believe McLean had fled after his two cellphones were made inactive the day before Allison and Jozee were killed. When investigating at his Fulton residence, investigators found his car and a smoldering burn pile with both cellphones. He was not there.

McLean was an over-the-road trucker with ties to Columbia, Fulton, St. Peter, Minnesota, Chicago and Las Vegas as well. Authorities had no reason to believe he had fled in a semi, Leer said. 

The investigation into the Abitzes' deaths is ongoing as investigators work to complete the timeline of events. 

Their deaths were reported nationally and internationally. The U.S. Department of Homeland Security reached out to the Boone County Sheriff's Office seeking a description of McLean for use at checkpoints in case he tried to leave the country at the borders or by airplane.

"We worked with a lot of federal agencies to get the word out, get his picture out," Leer said.

Family members of McLean have been interviewed.

There is no suspicion at this time that anyone helped McLean evade authorities, Leer said.