Ryan Lee Matthew Taylor, 29, has been charged with felony second-degree murder in Thompson's death, on top of other charges.
The North Carolina State Highway Patrol reports Taylor failed to slow down as he approached a vehicle with Thompson and other teens inside, causing the collision. They add he tried to run from the scene before he was caught by authorities.
Taylor had his license previously revoked due to pending speeding and impaired driving charges.
At the scene of Saturday's crash, SHP determined Taylor was impaired by a controlled substance.
In an exclusive interview with ABC 11 following Wednesday's memorial service, Keith Hargrove, Kasi's father, shared memories of his late daughter.
"She was definitely dedicated to her school, schoolwork and classes," Hargrove noted, adding she took AP and Honors courses, as well as classes at a local community college to prepare for a four-year college.
Hargrove called on people to take responsibility for their actions and vowed to be at Taylor's court appearances.
"I'm not going to let this go," he said. "I'm definitely going to get justice, not only for my daughter but for the other teenagers that were in that vehicle, that are suffering right now. It's not only about my daughter, but other families that are crushed as well."
Hargrove said Taylor's pending charges, and SHP's determination that he was under the influence during Saturday morning's crash, added to their pain.
"Someone who had two pending Driving While Impaired charges, and that third one took her away from myself and the family that loves her dearly. Devastating. Loss for words."
Following Thompson's burial, family and friends participated in a balloon release, letting white balloons fly into the sky in her honor.
Hargrove shared what he'll remember about Kasi.
"That big, ole smile. We went on a lot of vacations and trips, but that smile was always number one. She was the sunshine of my life, and everyone's life behind me here today. Outstanding young lady," he said.
Hargrove said he has spoken with family members of other victims, adding some were in attendance Wednesday.
Elijah Brown, a fellow teenager in the vehicle with Thompson during Saturday's crash, was airlifted to Duke Hospital.
A hospital spokesperson said he remained in critical condition as of Wednesday afternoon.