A popular American crime podcast is trying to get to the bottom of a string of unsolved London murders from the 1960s and early 70s.

The podcast, Jensen & Holes: The Murder Squad, just released an episode searching for clues about the so-called Forest City Killer. It includes the death of 15-year-old Jackie English, whose family marked the 50th anniversary of her disappearance in October.

The podcast is hosted by investigative journalist Billy Jensen and retired cold case investigator Paul Holes and features a new case each episode, most which are unsolved. For the London episode, the duo took inspiration from a new book called The Forest City Killer by local bookstore owner Vanessa Brown.

Jensen spoke to London Morning from Los Angeles about why he's investigating and how he plans to do it.

What did you learn about the London case?

There was a 15-year-old girl named Jackie English in 1969. She went missing and her body was found in a creek five days later. There were signs of sexual assault. There was DNA, cause of death was blunt force trauma, and they still haven't solved that case.

Jackie English's family marked the 50th anniversary of her disappearance in October. (The English family)

That case opened up a pattern (to me) of how many people were being murdered in your city. And it really was considered, and this is something that I didn't even know until I was introduced to this case this year ... but London was considered sort of the serial killer capital of Canada.

What are the odds of finding the killer now, long after the murders?

I think the odds are pretty good.

It all depends on the evidence and how the evidence has been maintained. We know there were actually two semen samples, one was on her underwear which were found strewn on a highway ... if we were able to pull DNA from that and be able to use familial DNA the same way we were able to catch the Golden State killer, there's a good chance we can find this guy.

Just because this was so long ago, that doesn't make any difference. If the evidence has been maintained and if it's there, game on.

Have you been in contact with London police? Do they know that you are looking into this?

They do not know that I'm looking into this.

We're getting a lot of tips in. As the tips come in, we sort through the tips and then we deliver them to the police and then start that right there. Sometimes we start with the police, sometimes we don't.

London police Insp. James McBride holds a composite sketch of a person of interest in the murder of English. (Western University archives)

I'm going to tell the police ... 'Listen I'll pay for this. The podcast will pay for this.' I never want to hear 'we don't have the resources to to run the DNA.'

We can get this done. We can do the genealogy. We never want to hear anything about that we don't have the funds in order to do it because, if it costs $10,000, it costs $10,000. We're able to do it. We're going to be able to get justice.

What have you learned about London in doing this?

There's a lot of remote areas to it ... there's a lot of forests. Whenever I'm looking at forests, I'm always thinking 'how many dead bodies are in that forest?' That's where my head goes.

When you have a place that's a lot of forest but you also have a city as well ... it gives a place for people to, if they want to do something really bad, it gives a place for them to deposit the bodies.

How does what happened here compare to murders elsewhere?

It is an older case and because it's an older case, that represents a lot of issues. It could be a matter of finding a suspect, but the suspect is dead.

I think this is a case where that can happen. You saw that with Jack the Ripper.

Jensen is soliciting podcast listeners for more information about this unknown man, who was found in the pages of English's diary. (The English family)

It's not as satisfying as what you want. It's not as satisfying as having a guy in cuffs and being able to say 'that's the guy' and having the family members be able to look that guy in the eye and say 'how could you do this?'

The idea how London had so many of these serial killers that were around at the time, there was something about what was going on in London.

To learn more about Jensen's investigation, tap on the audio player below.

Investigative journalist and co-host of The Murder Squad podcast Billy Jensen tells London Morning how his team will try and solve the Forest City killer murders from the 1960's. 8:23

These answers have been edited and condensed for length and clarity.