The Wyoming Investigators Association hosts its Homicide and Cold Case Investigations Conference every two years. The five-day school brings in more than two dozen detectives who trade tips and study techniques with nationally recognized experts.

Richard Walter is a forensic psychologist who worked more than 22 years for the Michigan Department of Corrections. He's an instructor at the so-called "homicide school."

Walter says a key to reviving cold cases is taking advantage of perpetrators' mistakes. He says unlike TV crime dramas, most murder cases are solved through difficult, meticulous detective work and not by finding smoking-gun evidence.