Documenting the case of 6ft 7 powerhouse Gary Vinter, who has a long history of violence culminating in a frenzied attack on a work colleague who he stabbed multiple times and then left to die.

Fellow inmates consider James "Porky" O'Rourke to be one of the most dangerous and violent convicts in the UK prison system. At the age of 22, he killed a man by dropping a slab of concrete on his head.

Mother of two Joanne Dennehy launched a knife attack on a man she had lured back to her flat before stabbing two men out walking their dogs. Now locked behind bars, Dennehy is one of only three women currently serving a whole life order in the UK.

Mark Hobson is a man with an extreme propensity for violence, a notorious British spree killer who bludgeoned to death his girlfriend then seven days later sexually assaulted and killed her twin sister.

Covered in tattoos, his terrifying appearance adds to Jaime Osuna being one of the most feared men in the US prison system. Awaiting trial, he began practising Satanism and attempted to kill a fellow inmate.

Edward Johnson was sent to prison for the brutal murder of a female friend, but the violence didn't end there.