BOULDER COUNTY, Colo. -- The driver of a Nissan vehicle suspected of hitting and injuring a 19-year-old Boulder woman early Tuesday, turned himself in.

However, Colorado State Patrol troopers are still looking for a second driver who ran over the injured woman on the highway, just moments after the initial crash. Investigators said the second impact caused the injuries that killed the woman.

A spokesman for CSP told 7NEWS Tuesday that Jeremy Raisch, 34, contacted them around 11 a.m. Tuesday, more than nine hours after the hit-and-run was reported. Investigators believe Raisch was driving a black 1999 Nissan Pathfinder northbound on U.S. Highway 287 when he struck the woman and fled, the CSP said.

Cerridwyn Ursula-Lujan was standing in the middle of the highway, facing traffic, when she was struck at 1:22 a.m., according to investigators. She was struck near Vermillion Road, north of Longmont and was airlifted to Denver Health Medical Center, where she was pronounced dead.

"I'm just devastated," Judy Lujan said about her daughter. "She was just a wonderful kid, and I hope something good can come out of this horror," Lujan told 7NEWS reporter Lane Lyon Tuesday.

Ursula-Lujan, who was known by close friends and family as Kerry, attended Boulder High School and had plans of attending college.

"She brought everything to life around her," said Dr. Tink Tinker, a friend of the Lujan family. Tinker said he met Kerry and her mother around 10 years ago through the 4 Winds American Indian Council.

Tinker, who is also a professor at the Iliff School of Theology, said Kerry was proud of her American Indian heritage.

"She was always smiling," Tinker said while adding he hoped for a thorough investigation.

CSP said Raisch was not hurt in the crash. The Windsor resident was arrested and transported to the Boulder County jail. He is being held on suspicion of leaving the scene of an accident, a felony, and failing to report an accident to police, a misdemeanor.

Investigators said Ursula-Lujan may have been hitchhiking when she was walking along the highway. The CSP said alcohol may have been a contributing factor. Her toxicology reports are pending.

After further investigation, the CSP said there was a second driver that struck Ursula-Lujan as she lay on the highway and they want information that could lead to that person's arrest.

Trooper Gilbert Mares said a Good Samaritan stopped and tried to position his own car to protect the woman in the road after the initial impact, but couldn't prevent the second car from running over the injured woman.

The CSP wants to hear from anyone who may have more information about the crashes. Please call 303-239-4583.