Boulder County prosecutors said Grote was linked to a kill list by a 15-year-old boy, who is behind bars.
Funeral arrangements for Grote are underway, according to family members. A memorial for her is being planned for Sunday at Colorado National Speedway in Dacono.
“She started to be real competitor out there for us,” said close family friend and fellow racer Curtis Heldenbrand.
The Longmont Police Department said the Green Mountain High School graduate was at an apartment in Longmont when the suspect knocked on the door with a hunting knife in his hand.
The motive is still unclear, leaving family members and friends with many questions.
“She was the sweetest girl,” Heldenbrand said. “She had a passion for everything. … Her smile was contagious.”
Grote, a a star race car driver, was also active in softball and theater, according to Heldenbrand.
Plans are in the works for the public funeral to be held at the speedway with the Grote's hearse on the track. Fellow race car drivers plan to make one final lap in honor of Grote.
Gates at the speedway will open at 1 p.m. Sunday.