Irving Shuman (5 of Diamonds, Arizona)

When a Jewish activist and philanthropist didn’t show up for dinner, his friends and girlfriend didn’t know what to expect. In a matter of minutes, their lives would change forever. Strangled to death in his Phoenix real-estate practice’s office in September 2008, Irving Shuman’s family, co-workers and religious community were baffled. It’s been almost 15 years since Irving’s death, and investigators are still hoping for the tip that’ll break this case wide open.