Karr, who was jailed in Thailand for sex crimes, reportedly confessed to killing 6-year-old JonBenet Ramsey at the family's home on Dec. 26, 1996 and was being brought back to Colorado to face charges.
Ramsey said he was impressed with the international effort to solve his daughter's slaying but refused to speculate about the case, saying, "The justice system needs to run its course."
When asked by KUSA if he knew Karr, Ramsey said, "To the best of my knowledge, no."
Ramsey said his late wife Patsy knew authorities were closing in on a suspect before she died of ovarian cancer in June.
The Ramseys were named by local police as the prime suspects in their daughter's death but were never indicted and always insisted they were innocent.
They wrote a book, "The Death of Innocence," in 2000 and were eventually exonerated by DNA evidence.