A woman is dead and six other people are injured after a car collided with a trailer being pulled by a tractor in Kimball Township, Michigan, on Saturday night, according to the St. Clair County Sheriff's Office.

It happened just before 7:30 p.m. on Smiths Creek Road near Burns Road. The sheriff's office said a 79-year-old man was driving a tractor that was pulling a trailer with five people on it when the trailer was rear-ended by a Buick Regal driven by a 44-year-old man.

An 85-year-old Kimball Township woman on the trailer was taken to the hospital where she later died, officials said. 

According to the sheriff's office, the four other people on the trailer were also taken to the hospital: a 77-year-old Kimball Township woman who suffered serious injuries, a 67-year-old St. Clair Shores, Michigan, woman, a 62-year-old Kimball Township woman and a 54-year-old Kimball Township man, who each sustained minor injuries.

The man driving the tractor, from Kimball Township, was in critical condition at the hospital on Sunday, according to officials. The Buick driver, also from Kimball Township, was treated at the hospital for minor injuries.

Investigators said it appears the tractor was traveling without proper rear lights or a slow-moving vehicle emblem when the crash happened.

The investigation is ongoing.