Over a period of about twenty years Fred and Rose West abducted, tortured, raped and murdered an unknown number of girls, many of whom lay buried in the garden until the police dug them up. What motivated West to commit such terrible crimes? Was he born evil or did his upbringing make him this way? Did he do it for sexual kicks? Or, as some allege, did he supply the sacrificial victims to a black magic coven?

When the discovery of human flesh blocking the drains of an address in London led to the arrest of 37 year old civil servant Dennis Nilsen, police were staggered when he calmly told them he had killed at least 15 young men. At the time, Nilsen would go down in history as Britain's most prolific serial killer, and as police interviewed the matter-of-fact Scot, they uncovered the extraordinary story of a man obsessed with death since childhood. The lonely job centre executive would strangle his victims and keep their corpses for company, sitting them in chairs, talking to them and watching television together, before butchering burning or boiling the body-parts. Was Dennis Nilsen obsession with death fused during his childhood? Or, was his instinct to kill hard-wired from birth?

When body parts began washing up on the beaches of a peaceful Californian seaside town, police realised someone was hunting, abducting, murdering and dismembering female co-eds. What they didn't realise was; the killer was in their midst - drinking with them at their favourite local bar. Cops considered the 6'9' inch Edmund Kemper a gentle giant, little did they know that as a teenager he'd murdered his grandparents, he'd fooled psychiatrists into releasing him from secure hospital after just 5 years, and while he was socialising with police officers he was living out his bizarre sexual fantasies with the corpses of young co-eds. Edmund Kemper would kill and dismember 6 young college girls before turning on his mother and her best friend. Was his mind was twisted by his upbringing in a broken home and volatile relationship with a domineering mother? Or was the Co-ed Butcher born to kill?

In 1958 the real ‘Natural Born Killers’, Charles Starkweather and his teenage girlfriend Caril Ann Fugate, embarked on an 8-day killing spree that left 10 people dead and many more fearing for their lives. The duo was captured in January 1958 and Starkweather was executed on the electric chair little over a year later…

In 1982, when the bodies of 3 women were discovered beneath the surface of Seattle's Green River, no-one realised that it was the beginning of an extraordinary killing spree that would baffle police for 19 years. The 'Green River Killer' would become the most prolific serial killer in US history, claiming the lives of more than four dozen victims, but it would take until 2001 before DNA testing solved the mystery of his identity. To his friends and family, Gary Ridgway was a mild mannered truck painter and a loving husband, but for 19 years he had prowled Seattle's red light areas, picking up young women, strangling them during intercourse, dumping their bodies in the woods, and sometimes returning to have sex with the corpses. Featuring video of his startling confessions - the cops that pursued him, the attorneys who prosecuted and defended him, leading experts, school-friends, and the wife who spent 16 loving years with her dream man, attempt to unravel what had created this monster. Had he been warped by his unusual relationship with mother? Or was the Green River Killer a product of nature - born to kill?

Once dubbed 'the most dangerous man in Britain', Patrick Mackay was responsible for a string of bizarre murders during the 1970s. Was Patrick Mackay born to kill?

During the summer of 1980, Douglas Clark and Carol Bundy carried out a series of shocking murders in Los Angeles, leaving a trail of blood in their wake

He was one of the infamous serial killers in modern American history. Better known as the Boston Strangler, De Salvo’s reign of terror claimed at least 13 victims. A violent sexual deviant, he confessed to all the murders – yet some doubt his authenticity.

In 1979, a violent crime spree rocked the town of Richmond, Virginia. The discovery of a triple murder led police to a local gang of brothers.

When eccentric Hadden Clark was arrested for the murder of a young girl in Maryland, he claimed he was also responsible for other murders. Was Hadden Clark Born to Kill?

Spine-chilling documentary series examining serial killers. After being convicted of attempted murder and kidnapping, David Carpenter went on to kill five women.

Grisly documentary series examining serial killers. This edition examines the chilling case of Bobby Joe Long who raped 50 people and murdered nine.

He was known as the ‘Killer Clown’, and buried his young male victims under the crawl space of his suburban home. John Wayne Gacy was a monster in human form – a pillar of the community who viciously snuffed out the lives of more than thirty men. He’d prowl the streets at night, luring hitchhikers and runaways back to his home where he’d torture and kill them. Gacy was found guilty in 1980 and sentenced to death…

Hearse driving redneck Donald Pee Wee Gaskins may only have stood 5'4" tall, but he would earn himself the nickname of the meanest man in America and become South Carolina's biggest mass murderer when police discovered his boasts of having his own private graveyard were real. Cops would eventually discover the bodies of 13 men women and children, but in prison Gaskins would claim to have killed more than a hundred - raping, torturing and then sinking their bodies in the swamps. And Gaskins would add to his tally in prison, pulling off the extraordinary murder of a death row inmate - blowing him up by remote control. But what created this feared psychopath and sexual sadist? Was it nature or nurture? The men that knew and pursued him, leading experts, and the loving daughter he confessed to examine whether Pee Wee Gaskins was born to kill?

In the mid-1970s, Donald Nielson aka the Black Panther committed a string of burglaries, armed robberies and murders in north-east England.

Following the story of the serial killer, Peter Sutcliffe, who between 1975 and 1981 murdered 13 females and became known as The Yorkshire Ripper. But how did he get away with the crimes for so many years and was it nature or nurture that turned this chilled out hard-working man into a serial killer.

Known as the Vampire of Sacramento, Richard Trenton Chase was a deranged monster who slaughtered men, women and children in a bloody rampage that shook the Californian State Capital…

Ted Bundy orchestrated a campaign of terror that stretched across the United States. Between 1974 and 1978 he lured a series of pretty, dark haired women to gruesome deaths. Described as handsome and charming, Ted didn’t fit the bill of a conventional murderer. Until the end, Bundy remained arrogant and defiant, choosing to conduct his own defence in the trial. Bundy was sent to the electric chair in 1989, whilst hundreds of people cheered his death outside the prison…

The Son of Sam would become the most notorious killer in New York's history. Shooting women or couples parked in lover's lanes, the mystery killer spread terror through the streets of the metropolis, leading young women to cut and dye their hair for fear of becoming the killer's next victim. Writing to the police and press, the Son of Sam would claim to relish his 'work' and that he was programmed to kill. A massive manhunt would lead police to David Berkowitz - a lonely young man, adopted at birth, who claimed he was commanded to do the devil's work by a neighbour's barking dog. So was the Son of Sam driven by demons? Wreaking a bitter revenge fuelled by mental illness? Or was he programmed from birth to be a serial murderer?

In 1970, a California doctor and his young family were executed and dumped in the swimming pool of their hilltop home. The killer believed that he was on a mission from God.

Spine-chilling documentary series examining brutal serial killers. This edition reviews the case of Levi Bellfield who murdered three women, including Milly Dowler.

Grisly documentary series examining serial killers. This edition examines the chilling case of Sean Gillis who stalked, raped and brutally murdered eight women.

By the age of ten, heavy metal fan Richard Ramirez was sleeping in cemeteries. He would go on to spread terror throughout Los Angeles, preying on ordinary citizens as they slept in their homes. The Satan loving, drug fuelled burglar would rape, murder, and mutilate, taking pleasure in making his victims pray to Satan before him. Men, women, children and the elderly all fell victim as the police raced to catch the killer who defied all known theories about serial murder. So, was the Richard Ramirez born to kill? Warped by drugs? Or, was the Night Stalker schooled in murder during his poor childhood in the tough Texan border town of El Paso?

The horrific case of Timothy Wilson-Spencer, who strangled five people in the 1980s. The case was historic as it was the first case solved with DNA evidence.

Made famous for Charlize Theron’s portrayal of her in the film Monster, Aileen Wuornos was executed in 2002 for the murder of seven men. A down-on-her luck lesbian prostitute, she lured her clients to remote wooded areas, and more often than not, shot them at point blank range. Tried and convicted in a Florida court, Aileen received 6 death sentences and spent a total of 12 years on death row…