The true story behind Joseph Naso's crime ahead of Death Row Confidential: Secrets of a Serial Killer 

Death Row Confidential: Secrets of a Serial Killer follows the Joseph Naso case and the long trail of evidence tied to four California murders. The series centers on new claims from inside prison walls and the effort to match those claims to real victims.

The new crime documentary series Death Row Confidential: Secrets of a Serial Killer debuts Saturday, September 13, at 9:00 pm on Oxygen. Further airings roll through the week and into the following weekend.

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The true story behind Joseph Naso

Joseph Naso was sentenced to death in 2013 for four murders committed across the 1970s and 1990s. The victims shared matching first and last initials, which drew the “Alphabet Killer” label in coverage at the time. According to BBC News (November 2013), the Marin County jury returned guilty verdicts for the killings of Roxene Roggasch, Carmen Colon, Pamela Parsons, and Tracy Tafoya.

The case moved after a probation search in 2010 uncovered thousands of photos of women and a handwritten “List of 10.” Investigators also located a safe deposit box key that led to IDs, clippings, and images tied to victims. Per SFGate (January 2012), prosecutors later used those items in court alongside diary entries that described assaults.

A 2010 probation search uncovered thousands of photos and a handwritten “List of 10.” (Image via Pexels)

Years later, a new thread emerged. ABC7/KGO reported that fellow inmate William A. Noguera gathered more than 300 pages of notes from conversations with Naso and relayed them to retired detective Ken Mains, including an alleged claim that the real number of victims reached 26 (September 2025). Those assertions remain the subject of ongoing review and are a core focus of the series.

The series places those prison notes next to missing-person files and unsolved homicides. The aim is to test what can be verified, which names can be attached, and which details hold up when compared with police records.

Families tied to older cases also appear, since several names on Naso’s “List of 10” were never publicly matched. That gap explains why the production leans on document trails, phone logs, and travel histories.

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How Death Row Confidential: Secrets of a Serial Killer approaches the story

Episode 1 introduces the collaboration between retired Detective Ken Mains and inmate informant William Noguera. The premiere follows the transfer of those notes and the first attempts to link clues to identified victims. Oxygen’s logline says the duo “expose the secrets of convicted serial killer Joseph Naso” and suggests he likely killed more women than first believed.

Episode 2 focuses on claims that Naso posed as a professional baseball team’s photographer as a way to approach women. The hour also tracks a possible stretch in Las Vegas based on time, travel, and name fragments found in the notes.

Episode 3 features a written confession obtained by Noguera and a look at cases in New York that may overlap with entries on Naso’s list. The production follows how a single paragraph can unlock a location, then a file number, then a name.

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What the record shows

Naso represented himself at trial and denied the murders. The death sentence followed a separate penalty phase after conviction. KCRA summarized the court’s findings and explained why executions in California remain on hold despite the sentence (November 2013).

The case proceeded to a 2013 conviction and a death sentence after the penalty phase. (Image via Pexels)

Evidence that drew attention included blood or DNA links in two of the charged cases, photographs that appeared to show victims unconscious or deceased, and entries in journals recovered from Naso’s home. Those details anchor the “true story” portion of the series and set a baseline for any new claims.

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Where to watch Death Row Confidential: Secrets of a Serial Killer

Oxygen lists the following airings. Times are shown across major U.S. time zones. First airs are marked.

All times in the table are converted from the ET schedule; check local listings for any changes.

Live on Oxygen, with on-demand streaming available after broadcast via the Oxygen app and website for authenticated subscribers.

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Also read: Is there a new episode of Cold Justice this week (13th Sept, 2025)? Explained

Edited by Preethika Vijayakumar