John Ramsey also once again asked for the public's help in solving the case, the Boulder Daily Camera reports. He released a statement Wednesday.
"We are hoping to jog memories and in doing so, asking everyone to examine their consciences," Ramsey said in a statement.
"We'd like them to share any doubts or information they have about someone they know who may have behaved strangely or acted out of character around the time of my daughter's murder."
JonBenet, 6, was last seen alive on Christmas Day 1996. Her body was found the next day in the basement of her parents' home in Boulder.
Ramsey and his wife, who died in 2006, were suspects for many years. Police now believe their daughter was killed by an intruder.
Lou Smits, a retired detective who works with Ramsey, says criminal profilers believe the killer might be someone perceived by others as cold. The killer may also have pronounced views on government or organized religion.