STANTON, Wis. — Authorities said further investigation of a Friday crash that left three people dead in western Wisconsin confirmed a downed stop sign was not a factor.

Rather, St. Croix County Sheriff Scott Knudson said deputies are looking into reports that motorcyclist Cody Cook-Terhurne was driving recklessly in the moments leading up to the crash, reported at 7:10 p.m. July 19 at Highway 64 and County Road T in the town of Stanton.

Deputies had been alerted to a downed stop sign at the intersection shortly before the collision, but Knudson said witnesses later confirmed the driver of the second vehicle, Thomas J. Plasch, had stopped at the intersection, which is preceded by rumble strips and a "stop ahead" sign.

Plasch, 55, of Oakdale, Minn., and his passenger, 46-year-old Oakdale resident Miriam R. Espinosa, were killed in the crash, along with Cook-Terhurne, a 34-year-old Somerset resident. Plasch's 2008 Lincoln passenger car was northbound on County Road T while Cook-Terhurne was westbound on Highway 64 when the motorcycle struck the car.

All three were pronounced dead at the scene, according to the sheriff's office.

The release cites witness reports that the motorcycle was "traveling at a very high rate of speed" just before the crash and had been passing vehicles on the right shoulder.