Many people know of the Clutter family murders in Holcomb, Kansas in 1959 made famous by Truman Capote in his book about the case “In Cold Blood”. Most people have never heard of the Walker family. The entire family was murdered, in Florida a short time after the Clutter murders. 24-year-old Christine Walker was raped and murdered and the rest of the family shot to death, much the same fate the Clutters suffered.
The killers of the Clutters, Perry Smith and Richard Hickock, were arrested, convicted and hanged for the crime in 1965.
After killing the Clutters, Smith and Hickock fled to Florida and were in the area the Walkers lived when the murder occurred.
Florida detectives looked into the possibility that the pair had killed the Walkers, but dropped them as suspects after they passed polygraphs.
In 1959, polygraphs were notoriously unreliable. They are better today, but an experienced detective would never eliminate someone as a suspect because of a polygraph alone. Many killers passed polygraphs only to later be convicted, such as Gary Ridgway, (The Green River Killer), Ted Bundy, and Jeffrey Dahmer to name a few.
The bodies of Smith and Hickock were exhumed in 2013 to collect DNA. The DNA that was collected was too degraded to match with DNA from the scene.
If the DNA collected from their bodies was retained, it should be tested again. A lot has happened since 2013 to develope a profile from degraded samples.
If not that, detectives should use forensic genealogy link the DNA from the scene to relatives of the two. If they didn’t do it, (which I believe is unlikely) it may lead to the real killer.
An article about this case was posted on the website The Line up.