MADISON, Wis. (AP) — Authorities have arrested a suspect in the homicide last month of a 26-year-old man who was killed while running on a southern Wisconsin road.

Dane County sheriff's detectives arrested the 21-year-old Mt. Horeb man on Thursday in the Jan. 15 death of Nicholas Day of Blue Mounds, the sheriff's office said Friday. The suspect was in jail on a tentative charge of first-degree intentional homicide.

Authorities originally believed Day was the victim of a hit-and-run on a county road in the town of Blue Mounds. But an autopsy revealed Day had suffered a gunshot wound and had sustained several lacerations to his neck.

Authorities said the motive for the killing is unclear and they don't know a connection between the victim and the suspect.