The officer stopped the auto and found Rodriguez and Caitlyn safe. Police were investigating the "blossoming of a potential relationship" between Frisina and Rodriguez.
Caitlyn Frisina of Lake City had been missing since Saturday.
According to a missing persons report, Frisina left her home through her bedroom window, taking some clothes and her wallet but leaving her cellphone, which had been erased of data.
The 17-year-old, who played soccer at her Florida high school, may have been in a relationship with the assistant boys' soccer coach Rian Rodriguez, who was with Frisina in the vehicle when police intervened around 4 p.m. Friday. "We are so thankful to have her back".
Rodriguez was taken into custody without incident, and Caitlyn was detained, the Sheriff's Office said.
The pair was spotted at 4 p.m. Friday by a State Police investigator, Todd Grant, who recognized Rodriguez's red Mercury sedan and its Florida license plates. The FBI and U.S. Attorney's Office have been advised of this case and will consider federal charges in Florida.
17-year-old Caitlyn Frisina is believed to have left her home in Columbia County voluntarily sometime late Saturday night or early Sunday morning and was reported missing by her parents, according to the Columbia County Sheriff's Office.
Frisina and Rodriguez were spotted on cameras in Georgia on Sunday and then at a pawn shop in Fayetteville, North Carolina. Police say she is with her high school's boys' soccer coach, Rian Rodriquez, 27.
The Columbia County Sheriff's Office will hold a news conference at 2 p.m. Monday for more details.
Frisina has played soccer at Fort White High School, according to an online roster published by Next College Student Athlete.