KOOTENAI COUNTY, Idaho -

Kootenai County prosecutors have upgraded charges against a man accused in a road rage murder last month.

In a newly filed superseding indictment, David Hutto is now charged with kidnapping, robbery and arson. Prosecutors also upgraded his original charge from 2nd degree murder to 1st degree murder; that means they now believe they can prove the murder was premeditated.

Hutto is one of two men in custody in connection with the death of Bo Kirk. Detectives believe Kirk was kidnapped just outside his home, then shot and killed at the Hayden Creek Shooting Range. His truck was found in flames several miles away.

The other man charged in the case remains in federal custody. Justin Booth was Hutto's roommate and business partner and voluntarily gave a statement to detectives. He said he traded some mopeds for a handgun in the weeks before Kirk's murder. The gun was found in their shared Coeur d'Alene home.