Friends that vanished while on hike left disturbing photo on their phones beforehand

A decade ago, friends Kris Kremers and Lisanne Froon vanished while on a hike on Panama's 'El Pianista' trail.

They went missing on 1 April, 2014 and it was several months before body parts were found.

Kremers, 21, and Froon, 22, had been planning the hike for months and are believed to have travelled through a forested area near the Baru volcano in Boquete, Panama.

However, they were never seen alive again and despite an extensive search being launched, it wasn't until June that more clues were uncovered.

Someone handed over Froon's backpack, saying they found it by a riverbank, which contained money, water, two phones and a camera.

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

The phones showed that about six hours into the hike, both phones had been used to try and call the emergency services, but a lack of signal meant the calls never got through.

The women had dialled 112, an international emergency number, and 911, Panama's national emergency number.

Further investigation found that Froon's phone, a 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.

That could mean that someone was entering the wrong PIN, or that nobody was entering a PIN and was just checking to see if there was any signal.

The iPhone belonging to Kremers was switched off for the last time on 11 April.

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

Among the photos found on the camera were disturbing ones which suggested that there had been an accident.

There were photos of the women's belongings all laid out on some rocks, while another showed the back of Kremers' head.

A number of pictures had been taken in the early hours of the morning of 8 April, with dozens of flash photography pictures snapped between 1am and 4am that day while it was dark.

The scant information left behind has resulted in plenty of theories of what happened to the two women.

The discovery of Froon's backpack resulted in fresh searches near where it had been found, and denim shorts belonging to Kremer had been found on top of a rock on the opposite bank of the river, a few kilometres down from where the backpack had been found.

Two months later, a pelvis and a boot with a foot inside were found, and testing confirmed that the remains belonged to the two women.