After Edmund Kemper killed and decapitated his mother, he tore out her vocal cords and shoved them down the waste disposal.
Edmund later told police that as the gristly innards were spat back in to the sink, he’d thought “that seemed appropriate as much as she'd b*****d and screamed and yelled at me over so many years."
The American serial killer was responsible for the deaths of eight women between May 1972 and April 1973.
Six of his victims were hitchhikers who he killed by shooting, strangling or smothering, their lifeless bodies taken back to his house, dismembered and raped.
He later told police his biggest thrill came from removing their heads, explaining: “I remember there was actually a sexual thrill - you hear that little pop and pull their heads of and hold their heads up by the hair.
“Whipping their heads off, their body sitting there. That'd get me off.”
The final two victims were people he knew, his mum Clarnell and her best friend.
Things had never been plain sailing between the mum-of-three and her only son, and he would later claim that his hatred for her motivated him to kill.
In a 1991 interview he said: “Before I murdered my mother I said ‘she’s gotta die, I gotta die or girls like that are gonna die.”
As a child, Edmund was already tall – he’d later grow to 6'9" - which made him stand out amongst other children at his school in Montana.
He also showed signs of psychopathic behaviour, including extreme cruelty to animals.
At the age of 10 he buried the family cat alive, only to dig it up weeks later and decapitate it; Edmund then put the creature's head on a stick - the first example of a disturbing pattern to come.
Three years later he killed another family cat after believing it preferred his younger sister.
He even hid some of its body parts in his wardrobe - until his horrified mum discovered them.
Killing animals wasn't the only unsettling behaviour that Clarnell had to deal with.
Edmund would perform 'funeral rites' on his sisters' dolls, decapitating them and removing their hands. He also made his siblings play along with 'games' where he pretended to be strapped to an electric chair or suffocating in a gas chamber.
Eventually, Clarnell became so concerned he would rape his sisters that she made him sleep in a locked basement.
Aged 14, and standing nearly 6’4”, Edmund ran away to California to track down his dad and was horrified to learn he had remarried and had a stepson around the same age as him.
It became clear that Edmund Sr didn't want his biological son around. Edmund was sent back to his mum in Montana, but she didn't want him either so he ended up with his paternal grandparents in California.
He also loathed his grandma, and saw her as being similar to his mum, saying in a 1991 interview: “They were both aggressive, matriarchal women, they’d been the daughters of matriarchal women.”
Grandma Maude Kemper was to become his first victim.
On August 27 1964 when Edmund was 15, he rowed with Maude about him going out to shoot birds. He shot her in the head and twice in the back using the rifle his grandad - also called Edmund - had given him.
Afterwards, he calmly hid her body and waited for his grandad to come home from the store - an excursion Edmund had refused to accompany him on.
Afraid of getting in to trouble, Edmund shot his grandad when he arrived home. He later said it was to spare him the pain of seeing his wife dead.
Their bodies still warm, Edmund called his mum to tell her what he had done and then phoned the police, patiently waiting on the porch to be collected and taken to the local station.
Edmund was diagnosed with paranoid schizophrenia and sent to Atascadero State Hospital - where doctors discovered no signs of mental illness at all, just an incredibly high IQ of 145.
During the next five years, Edmund befriended his psychiatrists and was acting like an assistant, helping them develop and carry out tests to diagnose sociopaths – and simultaneously learning how to use the tests to manipulate his doctors.
He later admitted he also learnt from the rapists he performed the tests on, discovering that it was best to kill a woman after raping her to eliminate witnesses.
In 1969, on his 21st birthday, he was released from the hospital back into his mum's care, with his juvenile records wiped as he reached legal adulthood.
By this time he was fully grown at 6’9” and weighed 21 stone - a bulk that would make him impossible to fight off.
Edmund attended a local college as per his parole requirements, but his hopes of becoming a state trooper were dashed as he was too tall.
He took on menial jobs and eventually a role at the Highway Department, which allowed him to learn about secluded areas of woodlands and deserted roads that were ideal for murder and rape.
He continued to hang out in bars popular with cops so he could listen to their anecdotes, maintaining a good relationship with local officers who knew he had been eager to join their ranks.
But back home he continued to fight with his mum, having arguments that the neighbours could hear - and that he said would have come to blows had she been a man.
In an interview he said: "My mother and I started right in on horrendous battles, just horrible battles, violent and vicious.
"I've never been in such a vicious verbal battle with anyone.
"It would go to fists with a man, but this was my mother and I couldn't stand the thought of my mother and I doing these things.
"She insisted on it, and just over stupid things. I remember one roof-raiser was over whether I should have my teeth cleaned."
Edmund managed to move out of home, he said that she was never far behind, calling him constantly to make demands and making unscheduled appearances at his home.
Despite trying to make a living, Edmund often had to move home to his mum’s if he was short of cash for rent, and to recover after being involved in a motorcycle accident.
But their relationship was worsening by the day, and a huge row could trigger a trip out in his yellow 1969 Ford Galaxie - which he had packed full of handcuffs, plastic bags, knives and blankets, tools he thought might come in handy for a murder.
Edmund estimated that he picked up at least 150 hitchhikers and let them go without harm before getting the sexually homicidal urges he referred to as "little zapples" that saw him pick up six different women, rape them, decapitate them, and rape them again.
A 1974 crime magazine reported him as saying: “"At first I picked up girls just to talk to them, just to try to get acquainted with people my own age and try to strike up a friendship.”
But he told police that he started to have sexual fantasies about his passengers, as well as being worried he would be convicted of rape.
He added: "I decided to mix the two and have a situation of rape and murder and no witnesses and no prosecution."
The first victims were Mary Ann Pesce and Anita Luchessa, students who he promised to drive to Stanford University on May 7 1972.
In reality, they ended up in pieces in his bedroom, but not before he had raped both of their corpses and taken explicit photos of them.
He also sexually assaulted their decapitated heads before throwing them in to a ravine and dumping bags of their body parts on wasteland.
It wasn't until September of that year that he would kill again, picking up a 15-year-old hitchhiker who had missed her bus to dance class.
Aiko Koo was choked unconscious before being raped, murdered and put in the boot of his car.
Edmund went for a drink before taking her home, raping and dismembering her.
January 7 1973 saw the murder of Cindy Schall, who he shot and then stored in his wardrobe overnight.
The next day, after his mum had gone to work, he raped her before dismembering and decapitating Cindy using a power saw in his mum's bath, burying her head in the garden under her window.
He later quipped that he had chosen to place her there as his mum had "always wanted people to look up to her."
A month later on February 5, and after a huge argument with Clarnell, Rosalind Thorpe and Allison Liu were shot when he picked them up hitchhiking.
This time he beheaded them in his car and then wrapped their bodies in blankets before bringing them in to the house to be raped and stored overnight.
Edmund later told cops why he would remove the heads, saying: "The head trip fantasies were a bit like a trophy.
"You know, the head is where everything is at, the brain, eyes, mouth.
"That's the person. I remember being told as a kid, you cut off the head and the body dies.
"The body is nothing after the head is cut off. Well, that's not quite true, there's a lot left in the girl's body without the head."
His final victims were killed on April 20 - and one was his mum.
Clarnell, 52, returned home from a party and seeing her son in the doorway, sighed that he would probably want to "sit up all night and talk".
He replied: "No, good night", before waiting for her to fall asleep and bludgeon her to death with a claw hammer.
Later Edmund admitted he also slit her throat, raped her head, placed it on a shelf so he could "scream at it for an hour and throw darts at it" and then smash it.
Her tongue and vocal chords went down the waste disposal but they were too gristly and were spat back out in to the sink.
He raped his mother's corpse then put her in a cupboard and popped out for a drink.
When he came home he called his mum's best friend Sally Hallett, 59, and invited her over for dinner and a movie - and invitation she accepted.
Edmund strangled her, beheaded her then sat up all night with her body before shoving it in a wardrobe.
The next morning he left a note in the house reading: "Appx. 5:15 A.M. Saturday. No need for her to suffer any more at the hands of this horrible "murderous Butcher". It was quick—asleep—the way I wanted it. Not sloppy and incomplete, gents. Just a "lack of time". I got things to do!!!" and drove eastwards to Colorado.
Upset he hadn't heard anything about his mum's death on the radio he called police and handed himself in.
Edmund was 24 when he went on trial in October 1973, and after five-and-a-half hours of deliberation by the jury, he was handed eight life sentences.
Netflix series Mindhunter is based on the true story of FBI agents who spoke with genuine serial killers and psychopaths to help them crack crimes.
Furthermore, the discussions that they have with the monsters on the show are taken from REAL interviews the killers did while behind bars - and one of them is Edmund Kemper, The Co-Ed Killer.