A teenager’s terrifying last moments as her best friend and her boyfriend stabbed her to death were filmed and then posted online by the sick pair, say police.

The mutilated body of tragic Tamyres Lima da Silva was found in a shallow grave amid a thicket in Crato, Brazil, on 31st January, four days after she went missing.

Harrowing footage seen by Newsflash of her terrifying final moments shows Tamyres, 18, cowering helplessly as a man stabs her repeatedly in the back of the neck.

As she makes a desperate bid to flee, the same man picks up a heavy rock and launches it at her head.

He then restrains her on the ground as he finishes her off.

Some images show Tamyres with what appears to be blood pouring from the back of her head.

The shocking footage was then shared on WhatsApp groups, say police.

They accuse Tamyres’s best friend – 18-year-old Milene Alves Rodrigues – and Rodrigues’s boyfriend of taking part in the crime, along with others.

Rodrigues – who reportedly lived with Tamyres – was arrested by police.

It was during questioning that she admitted where she had last been with her best friend, leading investigators to the shallow grave.

Tamyres’s body was clearly identifiable through her distinctive tattoos.

Civil Police are investigating the case.

Local media did not report on a possible motive.