The father of JonBenet Ramsey is making a public plea for help in finding his daughter's killer 13 years after she was found strangled in the basement of her family's Boulder home.John Ramsey said in a statement Wednesday that he is asking people to share any suspicions they had or recollections of people acting strangely around the time the 6-year-old girl died.JonBenet, a 6-year-old Boulder beauty pageant contestant, was found dead in the cellar of her parent's home on Dec. 26, 1996. She had been bludgeoned and strangled. Her parents went on CNN several days later and the case eventually attracted worldwide attention. A former prosecutor said Ramsey and his wife, Patsy, were "under an umbrella" of suspicion, but authorities cleared them in 2007. Authorities said new DNA tests pointed to an unknown outsider. Police continue to investigate the case. The case was turned back to Boulder police earlier this year, six years after police turned the probe over to the district attorney amid public criticism of how officers had handled it.Police said more than 140 people had already been investigated as potential suspects, but none could be linked to the crime. Patsy Ramsey died from cancer in 2006.