A Stoughton man was arrested Tuesday on a tentative charge of homicide by negligent operation of a vehicle in connection with a crash last month near McFarland that killed his girlfriend.

Richard J. Nelson, 22, was driving south on Highway 51 when he lost control on the shoulder of the road while trying to pass another vehicle. Nelson’s vehicle then crossed the center line and struck a northbound car driven by Mark Stutman, of Pennsylvania, the Sheriff’s Office said.

The Dane County Sheriff’s Office said excessive speed was a factor in the crash.

Two passengers were thrown from Nelson’s vehicle, including Andrea R. Garcia, 19, of Madison, who died at the scene. Bradford G. Anderson, 20, of Stoughton, suffered life-threatening injuries but has since been released from the hospital.

Stutman’s wife, Pamela, who also suffered life-threatening injuries, remains at UW Hospital, where she was listed in good condition Tuesday.