The investigation continues for retired Detective Ken Mains and death-row inmate informant William “Bill” Noguera on Death Row Confidential: Secrets of a Serial Killer. Oxygen’s latest docuseries concludes with back-to-back episodes on September 20 as the unlikely pair look to crack more cold cases tied to convicted murderer Joseph Naso, who claims to have killed 26 women. He lured women under the guise of being a freelance photographer. Authorities found a handwritten diary in Naso’s Reno, Nevada home where he listed 10 nameless women with geographical locations. He would sexually assault his victims and photograph them in sexual poses alongside mannequins. 

In 2013, Naso was convicted of four counts of first-degree murder and sentenced to death for killing four women. He became known as the “Alphabet Killer” as some of his victims had the same initials for the first and second names, including Carmen Colon, Roxene Roggasch, and Pamela Parsons. 

However, authorities believed there was the potential of more victims. Enter Noguera, who got to know the fellow inmate while serving his own sentience in San Quentin Rehabilitation Center. Noguera jotted down more than 300 pages of notes from his conversations with Naso, who confessed to killing 26 women. With all this information, Noguera ultimately reached out to Mains, a former FBI investigator, through a letter claiming to have information regarding other murders Naso committed. 

This sent them both down the rabbit hole as shown in the show. Naguera and Mains were in search of answers in hopes of bringing closure to the victims’ families. Meanwhile, Noguera was resentenced, which made him eligible for parole. He was convicted at age 18 for one count of first degree murder for killing his girlfriend’s mother. He told Mains shown in the docuseries that the mom forced his girlfriend to get an abortion, which sent him in a rage. Naguera looked to dedicate his own life to make amends.  According to Vanity Fair, he was released July 2 on $50,000 bail after 42 years. These moments are captured in the remaining episodes. Naso, 91, remains incarcerated. 

Here Mains and Noguera open up about their experiences captured in the project. 

What was it like having this docuseries chronicle the work and your investigations? Anything you took from the experience of having cameras there each step of the way?  

Ken Mains: It is something I wanted. I always want to get my investigations seen by as many people as possible. Our YouTube channel “Unsolved No More” has over 125,000 subscribers. So, combining those viewers with a national audience really increases the chances that someone will see something that can help the investigation. I continually tell the other people on camera not to look at them and pretend they are not there to get them comfortable. I honestly don’t see a camera when I’m working. I just do my thing, and they do theirs. 

Bill Noguera: The docuseries made this investigation real for a lot of people. Otherwise, no one but the victims’ families and law enforcement would have known about it. I feel that it’s important to put the information out there so that it opens people’s eyes and through the docuseries a witness may remember something that could help us solve another case when they come forward. Fireside Pictures did an amazing job in making the investigative process real for the world to see.

What do you want to say about what viewers will see in the final two episodes? 

Ken: You will see the true nature of cold case investigations. You’ve seen the highs already, solving a case and having the police tell you that you are right. But prepare now to see the lows. A lead not working out or just being wrong. Viewers will see more emotion as I meet with more family members. Ultimately you will also see me not give up and break through walls to solve additional cases because that’s what I do.

You were able to provide closure for a lot of these victims’ families and talk to them in person. What were those moments like? Was it difficult getting them to agree to be on camera?

Ken: It is always difficult because you are evoking emotions in them that may have laid dormant for decades. It is not easy by any means, and I don’t like to do it. However, they deserve to be told the truth. I live my life the same way as I approach cold cases, with honesty, transparency and truth. Fortunately, I didn’t have to worry about getting them on camera…that responsibility fell on someone else.

How would you describe your working relationship with each other and how it has evolved into this friendship? What do you remember from that first in-person meeting?

Ken: We have a mutual respect for each other and that has allowed us to work together seamlessly for the past three years. We do look at the world much in the same way and think alike when it comes to profiling offenders, so it has been very easy working with Bill. As to our first in person meeting I just remember thinking this man hasn’t been outside San Quentin in 40 years and was scheduled to be executed twice…and here he is going through all this…his mind must be spinning. 

Bill: Ken and I have a working relationship based on a mutual respect for the victims of these crimes. We have different approaches. But we agree, the victims are what matters. It is through this mutual interest that our relationship grew into a real friendship of respect, admiration and belief in each other. Ken is the guy at the end of the day I trust.

Bill, how was it getting to know Joe and building that trust for him to open up to you? Do you think at a certain point he knew what you were ultimately doing? 

Bill: Naso never knew exactly what I was doing. He often said I asked a lot of questions, but he never imagined I was there, next to him, offering protection, friendship with one goal in mind. And that was to bury him. I was on a mission. Every day I kept the victims in my sights. This was for them. As much as I wanted to get away from Naso because he disgusted me. I stayed for Charlotte Cook, Pamela Lambson, Lynn Ruth Connes, and the rest of the victims we will identify.

Bill, what has it been like reacclimating back into society? 

Bill: Returning to society to pay my debt is something I think of everyday. I’m grateful to the honorable Judge Lance Jenson, for believing in the evidence and ruling on facts, not through a political lens. I’m out to do a job, a job I gave my word I’d accomplish, and I will do exactly that. Solve cold cases.

Ken, you allude that your work is not done and that you’re in search of your “white whale” in the form of number 1 on “the list of 10” from Naso. Can we expect to see more from you on Oxygen?  

Ken: Those decisions are above me; I am just a detective, and that’s what I focus on. There is certainly enough material to continue more seasons but again, that’s not my call. There has been progress, but there is still a lot of investigating that needs to be done, and I intend on doing it and being successful just as I have been with the others on that list.

This docuseries is very much about Joseph Naso, but also you too as well. What kind of impact do you think the docuseries will have?

Ken: It is my hope that people see what real cold case investigations look like. I hope victims’ families see that there are people who care about them. I hope law enforcement will see that cooperation is the key to a successful outcome in cold cases. Egos have been the detriment of more cold cases not being solved than lack of evidence. Let that sink in. It is my hope that law enforcement will look at Daly City and Yuba County as examples on how to properly solve cases.

If you connected with Naso now, how do you think that would go?

Bill: He wouldn’t talk and he would deny everything just as he has done ever since his arrest. He is an upper-level narcissist who thinks he is the smartest guy in the room. Yet, he has never been in the same room as me.

Death Row Confidential: Secrets of a Serial Killer back-to-back episodes, Saturday, September 20, 9/8c, Oxygen