| Last updated
A new book to be published in August tells the true story of how a young couple from Greater Manchester were brutally tortured and murdered, before their killer lived free for four decades afterwards.
Chris Farmer and Peta Frampton were travelling around the world back in 1978 when they came across Silas Duane Boston, who offered to take them down to Belize on his boat along with his two sons.
They never made it there. The bodies of the two were found tied to discarded engine parts floating off the coast of Guatemala on 8 July 1978.
In the days before the Internet it was difficult to establish full communication between the two sides of the Atlantic, and investigations in the US - where the couple had boarded Boston's boat, the Justin B - and the UK had come to nothing.
However, in the Internet age, the families of the two victims convinced Greater Manchester Police to revisit the cold case in 2015.
They found that case files from a detective still existed, and also found Boston's two sons who had witnessed the events. They had tried to alert the authorities on several occasions, but to no avail.
At the time, Mr Boston denied killing the two and said that they had left his boat back in Guatemala, despite the two having paid for visas for Honduras.
But, once the police contacted Boston's now estranged sons years later, they spoke about how they witnessed the torture and murder of the two themselves.
WATCH: How did Cancún become Mexico's murder capital?
Vince Boston, who was only 13 at the time, told of how his father beat Farmer with a club and threatened Frampton with a spear gun. He also tried to stab Farmer with a fillet knife.
He then tied the pair up and put plastic bags on their head before pushing them overboard while they were tied to the heavy machine parts.
Their badly decomposing bodies were discovered by fishermen a good while later.
After this new information was revealed, Boston was tracked down and arrested. At the time, Greater Manchester Police said: "Greater Manchester Police Cold Case Unit have been working with the families of Christopher Farmer and Peta Frampton for over a year since relatives asked us to reinvestigate these tragic events.
"Since that time, we have worked closely with Interpol, Sacramento Police Department, the FBI and the U.S. District Attorney's office.
"The families of both Chris and Peta now await the outcome of a trial and would ask for privacy in the meantime."
However, it never got that far. Boston died in custody in April 2017. It is thought that Chris Farmer and Peta Frampton were not his only victims. One of Boston's sons suggested that it was an open secret in their family that his father had murdered his mother.
'Dead In The Water' by Penny Farmer, Chris' sister, is published on 9 August.
Chosen for YouChosen for You
Most Read StoriesMost Read