In the age of Facebook, it's difficult to hide your dirty laundry — even if you're a stone-cold serial killer.
In July 1978, Penny Farmer's brother Chris and his girlfriend Peta were murdered while boating in the Caribbean. The police identified a suspected killer — a fellow American named Silas Boston, who'd taken the couple on a boat ride prior to their disappearance. But despite all evidence pointing to the obvious, the case soon went cold.
So one afternoon, almost 40 years later, Penny Farmer decided to search the suspected killer's name on Facebook. His profile popped up immediately. There he was, looking like a "serial killer," thought Penny.
"Heaven knows why I didn't look earlier," Penny told the BBC.
In the photo, Silas wore a baseball cap, sunglasses, and a gray beard. Penny soon found his two sons, Russell and Vince, along with his fifth ex-wife.
Penny tried reaching out to the family directly, but she got no response. So she contacted the authorities. What unraveled next is truly stranger than fiction.
Penny's brother, Chris Farmer, and his girlfriend, Peta Frampton, went on a trip to the Caribbean in the summer of 1978. They were childhood sweethearts now in their mid-20s, off on an adventure.
Since this was pre-internet, Chris and Peta relied on snail mail to communicate with their families back home. But soon, communication stopped altogether.
The families notified the government and police, and an epic search began.
In July, their bodies were found floating off the coast of Guatemala. The autopsy showed that they'd been bound, tortured, and weighed down with engine parts, the BBC reports.
Peta's letters to her parents revealed that the couple had met an American and his two young sons in Belize. They decided to sail with the American on a small fishing boat to Honduras.
But when the American returned on his boat, Peta and Chris were gone.
The conclusion seemed obvious: They'd been killed by someone on that boat.
The American was identified as Silas Boston of Sacramento, California. He'd previously been accused of assault and rape, and his third wife (out of seven total) had disappeared 10 years earlier.
But his sons — who were on the boat along with Chris and Peta — were never interviewed. There was no crime scene investigation. And although Silas was questioned, he vehemently denied any wrongdoing.
The case went cold.
"It's difficult to imagine just how difficult it was back then, with no computers or mobile phones," Penny told the BBC.
She was 17 when her brother was murdered. After the tragic incident, she went on to graduate college, become a journalist, marry, and have three kids. Her father died in 2013.
But the haunting question of the murders of Chris and Peta never went away.
Then, in 2015, Penny had a light bulb moment. She decided to simply look up Silas Boston on Facebook.
Shockingly, she found him easily. After a long life on the run, he was living in California once again. Penny also found his sons, along with his fifth wife. She tried to message the family, but she got no response.
So she contacted the authorities instead. She now says she wishes she'd thought of using social media a whole lot sooner.
As luck would have it, authorities had just reopened the case into Silas' missing third wife. His sons say it was an open secret that their father had killed their mother.
And amazingly enough, they'd also spent much of the past 30 years trying to convince the police that they'd witnessed their father kill Chris and Peta in Guatemala.
Sons Russell and Vince informed the Sacramento Police Department, the Royal Canadian Mounted Police, the FBI, Interpol, Scotland Yard, and the Serious Organised Crime Agency. For years, none of those agencies acted.
At last, thanks to Penny's fateful Facebook search, the truth came to light.
Six months after looking up Silas on Facebook, Penny went to the police department with her mother — now in her 90s — and her older brother Nigel. The family read the witness statements from Silas' two sons. Later, Penny flew to California to meet one of the sons in person.
"It's quite incredible how much I know about what happened that day," she said.
"Boston was a rapist. My brother was in a very bad way, tied-up on the top deck. Peta was down in the cabin. I don't really need to say any more. I hope people can join the dots without me being too graphic."
In July, she released a book about the whole unbelievable experience, Dead in the Water.
"The really heart-warming thing was that even though Chris had a fractured skull and other broken bones, and there was blood all over the deck, he was still trying to comfort Peta, telling her it was all going to be alright. Even when they were trussed-up like turkeys, waiting to be thrown overboard."
Authorities tracked Silas down to a nursing home in Eureka, California. A caregiver had set up a Facebook page for him because he had no visitors or friends.
In earlier years, police suspected that Silas might be the infamous Golden State Killer, accused of terrorizing California in the late '70s and early '80s. They swabbed his DNA, but it came back negative.
Indeed, Silas was allegedly even worse than the Golden State Killer. According to Russell, his father claimed to have killed 33 people, while the Golden State Killer killed 13. Silas' sons say he even threatened to kill them if they told anybody about his crimes.
Fourteen months after Penny's Facebook hunt, Silas Boston was arrested and charged with the murders of Chris Farmer and Peta Frampton.
But the old man "took the coward's way out." He withdrew medical treatment and died in the hospital.
"Closure is a lovely term, and I do believe that closure only comes when the truth is known," Penny said.
"My mother is 93 and now has all the answers to the questions that haunted her for 38 years. But just because you've found answers doesn't mean you stop hurting. I'm not quite there yet."
