The Killer Speaks examines the 2006 murders of former corrections officer Rose Torres in Great Falls, Montana. Police arrest and later convict Gene Meredith for the murders. From prison, Meredith talks about his life and crimes. He claims that he is mentally ill and was driven to act by voices in his head.

In 1991, a human skull is found in the woods outside of San Antonio and a perfect murder begins to unravel. Investigators figure out the identity of their victim, but without witnesses or evidence, the case goes cold quickly. Until a career criminal in California makes a sudden and surprising confession, an admission that turns out to be less than truthful. Now, the killer describes what happened that night and why he confessed to the murder he could have gotten away with.

In Alamogordo, New Mexico, a young man is shot in cold blood and left to die on a remote mountain trail. As detectives hunt for the murderer, they worry they may be dealing with a potential serial killer who could strike again at any time. Now, the killer describes in detail how he murdered his victim and delivers a shocking revelation about his past.

In 1994, a mysterious drifter went on a violent killing spree leaving a trail of men, brutally killed. Investigators in three states soon realized that they were dealing with a serial killer, who never stayed in one place for long.

On November 15, 1999 the 24-year-old pregnant girlfriend of Carolina Panthers football player Rae Carruth is shot four times and left for dead in her car. Charlotte North Carolina Investigators suspect Carruth, but soon learn that this murder is not what it seems. They discover that they are dealing with a cold and remorseless killer where every murder has its price. Convicted killer Van Brett Watkins reveals the sordid details of the only "hit" he regrets doing.