In March 2014, two friends embarked on a life-changing trip to volunteer at a school in Panama.
But, after a hike through the jungle ended in tragedy, their story became one of the most chilling missing persons cases in history.
Kris Kremers, 21, and Lisanne Froon, 22, had travelled from the Netherlands to Panama to volunteer at a school and immerse themselves in the culture.
Advert
On 1 April, 2014, the pair set off on a hike on the Pianista Trail, near Boquete. They were never seen again.
Following their disappearance, authorities launched a massive search operation to find the friends.
Two months later, a pelvic bone and a foot, still inside a walking boot, were found alongside a blue backpack.
Advert
DNA tests confirmed that the remains belonged to Kremers and Froon, meanwhile the backpack contained their belongings, including a camera and two phones.
Both mobiles had been used to try and call the emergency services six hours into the hike. But due to a lack of signal, the calls never went through.
And, while the pair went missing on 1 April, authorities found a series of disturbing photos taken on their camera as far as seven days later.
The images, many of which had been taken at night, included shots of scattered belongings, weird angles and the back of Kremers' head.
Advert
Years later, what exactly happened to Kremers and Froon remains a mystery, but many true crime enthusiasts have offered their suggestions.
One chilling theory suggests that the women fell victim to foul play, believing that someone found them on the hiking trail, then kidnapped and murdered them.
They cite the weird behaviour and phone and camera activity as 'evidence' for the theory.
Advert
The photos on the camera are completely unexplained - although some say they may have been using the flash to scare away animals - and after the emergency calls on the first day, they stopped trying to make contact with the outside world.
On top of this, a full sweep of the area after the disappearance found no traces of the missing women, but some photos were taken days later.
And, their remains and belongings suddenly appeared months later. Some theorists believe that if they had simply suffered a terrible accident, the extensive searches early on would've brought up something before this.
Advert
While the remains didn't show any obvious signs of foul play, like the use of firearms or sharp objects, since so little of the bodies were recovered it can never be fully ruled out.
After taking a deep dive into all the evidence, Dutch authors Marja West and Jürgen Snoeren - who wrote Lost in The Jungle - believe the girls died after an accident.
But they admit there are a lot of 'unknowns'.
"We don't know if anybody was involved - we cannot exclude that," Snoeren told The Sun last year.
"We believe the most likely explanation is that they had an accident - but it's not 100 percent.
"The only way to make a full conclusion is when we find the rest of the bodies. I think there should still be remains there in the jungle from the girls. But it's a hell of a job."
Topics: Travel, True Crime, World News, Conspiracy Theory
Bec Oakes