America's most cold-blooded serial killer once fed six men at once to crocodiles

Warning: Contains graphic content

An American serial killer dubbed one of the most cold-blooded in history once fed six men to crocodiles during a horrific pattern of crimes beginning in childhood.

Criminologists who have attempted to explain his violent behaviour have often pointed towards his abusive childhood.

It wasn't long before Panzram turned to crime, committing his first theft aged just 12.

The crime landed him in a school where he was said to have been subjected to beatings and sexual abuse, and upon being released in his teens, he ran away from home.

While hopping train cars to get from place to place, Panzram was gang-raped, which he said left him 'a sadder, sicker, but wiser boy'. Soon, Panzram started inflicting violent acts of sexual assault on others, burning down buildings and robbing people.

He was actually arrested for theft in 1908, but it did little to rehabilitate him. Instead, when he was let out, he returned to his old ways.

The killer was caught several times for theft in the following years, but his violence quickly began to escalate.

In 1915, Panzram was handed seven years behind bars at the Oregon State Penitentiary for theft, during which he helped fellow prisoner Otto Hooker escape. While on the run, Hooker killed the penitentiary’s warden which in turn made Panzram an accessory, marking his documented involvement in a murder.

Shortly after, Panzram himself tried to escape the facility but was quickly caught and returned. However, it didn't deter him and he once again attempted to flee the following year.

Just a couple of years later, the criminal carried out one of the most twisted murder sprees in modern history.

In 1920, Panzram bought a yacht with money he'd stolen from former President William Howard Taft and began luring in American soldiers before raping them, murdering them and chucking their bodies into the ocean.

The killer later confessed to doing this to at least 10 men.

Just a few days after, he killed six local guides who were scheduled to take him crocodile hunting and fed them to the animals who, as he described it, 'devoured their bodies with gusto'.

Panzram would travel back to the States and continue raping and murdering young boys until 1928, when he was once again caught for theft and sent to Leavenworth Federal Penitentiary.

While behind bars, the killer confessed to the murders of two young boys, seeing his sentence bumped up to 25 years.

Though prison did little to stop his violent ways.

Ahead of his execution, he told the warden he would murder the first man who crossed him, which is exactly what he did when he beat the laundry foreman to death with an iron bar - a crime which would see him handed the death penalty.

In fact, he once said he was looking 'forward to a seat in the electric chair or dance at the end of a rope just like some folks do for their wedding night'.

In just one year, Panzram documented his crimes in graphic detail in his book Panzram: A Journal of Murder before he was ultimately executed aged 39 on September 5, 1930.

In total, it's believed he committed 21 murders, more than 1,000 acts of sexual assault and thousands of arsons and robberies.

Even in his final seconds, he showed no remorse for his crimes, apparently saying: "Hurry it up, you Hoosier b*stard! I could kill a dozen men while you’re screwing around!”