While studying vital clues in the form of audio files captured by a murdered woman's husband, police make a grim discovery.

While studying vital clues in the form of audio files captured by a murdered woman's husband, police make a grim discovery.

A male counterfeiter unknowingly leads investigators to storage unit that contains audio recordings of himself torturing dozens of women. Analysing the tapes, investigators begin to realise the counterfeiter may be one of the most depraved serial killers in history.

A male counterfeiter unknowingly leads investigators to storage unit that contains audio recordings of himself torturing dozens of women. Analysing the tapes, investigators begin to realise the counterfeiter may be one of the most depraved serial killers in history.

A mother is gunned down while next to her toddler, while police discover a Dictaphone that leads them on a trail of intimate audio recordings that could identity of her killer.

A mother is gunned down while next to her toddler, while police discover a Dictaphone that leads them on a trail of intimate audio recordings that could identity of her killer.

A woman finds herself in a predicament, being accused of murdering a stranger. She must find a way to clear her name, and begins secretly recording discussions - to obtain a confession from the man who is allegedly framing her.

A woman finds herself in a predicament, being accused of murdering a stranger. She must find a way to clear her name, and begins secretly recording discussions - to obtain a confession from the man who is allegedly framing her.

A fight between a couple ends in murder, leading investigators to find tape recordings - laying out a history of violence for the jury.

A fight between a couple ends in murder, leading investigators to find tape recordings - laying out a history of violence for the jury.

After returning home to find it burgled again, the retired man takes precautions to secure his Little Falls, Minn, home. On Thanksgiving evening, his peace is shattered by a home break-in, culminating in a gruesome double homicide; Investigators discover audio recordings of the killings, revealing what really happened and the killer's true motives.

After returning home to find it burgled again, the retired man takes precautions to secure his Little Falls, Minn, home. On Thanksgiving evening, his peace is shattered by a home break-in, culminating in a gruesome double homicide; Investigators discover audio recordings of the killings, revealing what really happened and the killer's true motives.