Final days of friends that vanished on hike and left disturbing photo on their phones beforehand

The harrowing case of two friends who planned to volunteer at a school in Panama ended in tragedy.

Two women from Holland embarked on what was supposed to be a life-changing trip to Panama back in March 2014.

Both from the same area, Kris Kremers, 21, and Lisanne Froon, 22, wanted to volunteer at a local school and immerse themselves in the culture.

The two women went missing on 1 April, 2014, but phone activity showed they were active for days afterwards (YouTube)

However, their story ended up becoming one of the most chilling missing persons cases ever.

It began when the pair set off on a hike on the Pianista Trail, near Boquete on 1 April, 2014, and never came back.

A massive search operation was launched, and even Dutch investigators came in to help with the potential rescue mission.

However, two months after no results, a local woman found a blue backpack belonging to Froon in a river near Alto Romero, far from where the women were last seen.

Photos found included ones of their belongings laid out on a rock (TVN2)

In the backpack were their belongings, which included a camera and two phones.

After authorities searched through the phones, it was concluded that 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.

One phone dialled 112, an international emergency number, and 911, Panama's national emergency number.

Froon's Samsung Galaxy S III ran out of battery on 4 April and was not used again, while Kremers iPhone 4 was turned on and off at times between 5 April and 11 April, but the correct PIN code was never entered.

Another bizarre shot. (TVN2)

Either someone was entering the wrong PIN, or perhaps nobody was entering a PIN and was, instead, just checking to see if there was any signal.

Meanwhile, Kremers' iPhone was switched off for the last time on 11 April.

Though, it was the disturbing pictures on the phone which shocked investigators as they displayed bizarre nighttime shots taken deep in the jungle, along with images of scattered belongings, unusual angles, and Kremers' hair. And the images were taken days after they disappeared, which is odd. The nighttime shots were taken between 1 and 4 AM on 8 April.

Sadly, after the discovery of the backpack, human remains were found, including a pelvis and a boot with a foot inside.

DNA tests confirmed that the remains belonged to Kremers and Froon.

While their remains were found, the case is still considered to have left many questions unanswered.