Sgt. Sheldon Lyon said passing motorists spotted Kecia King, 46, on the side of I-29 Saturday between 11 and 11:30 p.m. near Pickett Road in St. Joseph.
Sgt. Lyon said King died Sunday from injuries she sustained, but he is not sure if those injuries were a result of being hit by a car or something else.
The Highway Patrol is asking for any information that could help them determine how the woman ended up on the side of the highway.
"If a car struck her the driver of the car needs to come forward," said Sgt. Lyon. "If it was another reason of course we are going to investigate that and find out exactly what happened that night."
Call David Merrill at 816-387-2345 with any information.