On the early morning of February 1, 1991, 40-year-old Jackie Cardwell answered a knock at his Knoxville, Tennessee, home. His wife, asleep in the house, heard him speaking with a man and then a single, deafening shotgun blast. Cardwell was found gravely wounded at the door, taken to the UT Medical Center, and pronounced dead.

The killing remains an unsolved cold case: no arrests have been announced and no suspects publicly identified. Investigators have explored different angles over the years; one notable detail is a boating accident on Douglas Lake six months earlier in which two other men died. No definitive link between that accident and Cardwell’s murder has been established.

Who knocked on Cardwell’s door that night and why remains unanswered. Anyone with information about Jackie Cardwell, the February 1991 shooting, or the Douglas Lake accident is asked to come forward.