GENESEE COUNTY, Mich. -- Authorities said a mother of two was killed in a single-car crash in Genesee County Saturday.

Police said the crash occurred at about 5:30 p.m. on Duffield Road.

The woman's identity has not yet been released, but police said the 33-year-old Gaines Township woman lost control of her 2002 Pontiac Grand Prix and slammed into a tree.

Investigators said speed is believed to be a factor in the crash.

Police also said the victim was not wearing a seatbelt at the time of the crash.