Kal-el Sexton, 17 and his mother Dalahn Colley, 46, were killed in an early morning crash Saturday. Sexton was a senior at Sycamore High School.
Kal-el Sexton, 17 and his mother Dalahn Colley, 46, were killed in an early morning crash Saturday. Sexton was a senior at Sycamore High School. — Provided

SYCAMORE – A Sycamore High School senior and his mother were killed Saturday in a single-car crash on Plank Road, with the cause still undetermined, police said.

The DeKalb County Sheriff's office on Sunday confirmed that Kal-el Sexton, 17, of the 500 block of North Strack Street in Cortland, and his mother Dalahn S. Colley, 46, of the same address, were killed when their vehicle left the road and rolled over around 6 a.m. Saturday.

Colley, 46, of Cortland was not wearing a seatbelt and was ejected from the vehicle, according to the release. She was taken by Sycamore Fire Department ambulance to Northwestern Medicine Kishwaukee Hospital, where she was pronounced dead. Sexton, who was driving the 2006 Pontiac G6, was pronounced dead at the scene, police said.

DeKalb County Sheriff's Chief Deputy Andy Sullivan said it's not clear why the vehicle left the road.

"We don’t understand why it happened, really," Sullivan said Sunday. "That portion of the road was actually on the straightaway. He was taking his mother to work."

Sullivan said police investigators would be looking more closely at the Pontiac on Monday to try to determine if there was mechanical failure or some other cause. There was no indication that driver impairment was a factor, he said.

Sexton was well-known and liked by his classmates at Sycamore High. A senior offensive and defensive lineman on the Spartans' football team this year, he was known for his outgoing nature and was elected homecoming king this fall.

Although Sycamore students are now on winter break, many students who knew him were posting tribute messages on social media.