Serial killers tend to be methodical, psychopathic and well-organised murderers with twisted aims and distinct methods of going about their sick business.

Mass murderers, on the other hand, are usually much less thoughtful or complicated.

They amass sickening death tolls with few trackable clues, no specific targets and no set time period between murders.

For these reasons, they're also likely to kill many more than serial killers.

Richard Speck was thankfully caught after killing in the single digits during his infamous crime spree.

A criminal from a young age, Richard was inspired by his conman stepdad
A criminal from a young age, Richard was inspired by his conman stepdad

But his bragging about the thrill of killing a person suggests he would have taken the lives of many more had he been given the chance.

The seventh of eight children born to Illinois farmers, Speck's oldest brother Robert died in a car accident at the age of 23.

Speck's dad then died when Richard was just six, with his mum soon remarrying a career criminal and conman who was quite the opposite to his straight and narrow father.

Speck killed 8 nurses when he was 25, spending the rest of his life behind bars
Speck killed 8 nurses when he was 25, spending the rest of his life behind bars

At 12 he had his first drink, at 15 he was an alcoholic and when he was 13 he was arrested for the first time.

The psychological abuse of his stepdad took its toll and Richard was brutalised before he was even a teenager.

When he was 20 he married a 15-year-old girl who was quickly pregnant with his child.

Speck's worn face made him look much older than he really was
Speck's worn face made him look much older than he really was

By his mid-20s Speck became a criminal, following in his stepdad's footsteps, stabbing a man in an assault and robbing numerous corner shops in his local area.

But Speck's life unravelled further when his wife filed for divorce and - to his horror - remarried just two days after the divorce papers came through.

In April 1966 he broke and entered to a senior citizen's house, tying up the 65-year-old owner and raping her before stealing the $2.50 she earned as a babysitter that night.

Police had no doubts it was Speck who killed the women
Police had no doubts it was Speck who killed the women

This twisted turning point in Speck's life was only a hint of what was to come.

A week later he killed a young barmaid who worked at his favourite tavern, rupturing her abdomen with a single blow.

Police immediately suspected him of the crime as he had fled a local hotel, but Richard was well on his way and able to make an excuse for his sudden return to his sister's house nearby.

These student nurses were killed within days of the photo being taken
These student nurses were killed within days of the photo being taken

A few weeks later he committed his grisliest crime - and the one which would make him a national celebrity.

Speck broke into a dorm for student nurses and swiftly killed 8 young women with only a knife.

Reportedly he was drunk and high and only intended to rob the place, but got carried away.

Little did he know a ninth nurse was sheltering from his cruel spree, reporting him the next day - with his fingerprints found all over the dorm.

Eyewitness Corazon Amarao was sheltered after escaping Speck's cruel spree
Eyewitness Corazon Amarao was sheltered after escaping Speck's cruel spree

Speck was arrested four days later.

After being judged not insane by a panel of experts Speck's trial began, psychiatrists diagnosed him with OCD and as having a bizarre sexual obsession with women.

He was also diagnosed with a rare brain syndrome traced to early signs of trauma in his life - physical and mental.

The doctor's detailed reports weren't particularly useful to the trial, though, as he kept them for a book he published the next summer.

Speck was initially sentenced to the chair, but made an escape on a legal technicality
Speck was initially sentenced to the chair, but made an escape on a legal technicality

Speck was nevertheless found guilty after confessing the bulk of the crimes.

The jury spent less than an hour deliberating and the judge ruled he should get the electric chair.

A brief medical panic suggested he might've suffered from so-called XYY syndrome, but this was soon disproved.

Speck avoided the death penalty as a judge ruled too many jurors had refused to take the case for it to stand, but he was given life imprisonment and refused parole on seven separate occasions.

The funeral for the slain student nurses received widespread media attention
The funeral for the slain student nurses received widespread media attention

Nicknamed 'Birdman' by cellmates because of the sparrows which flew into his cell, Speck appeared to have a good time on the inside.

Recordings showed him gambling and drinking with fellow inmates, also taking drugs and on one striking occasion performing oral sex on them.

He said he was freer inside than he'd ever been on the outside and had no regrets for his crimes.

Speck commented: "Like I always felt... [I] had no feeling. If you're asking me if I felt sorry, no."

Sicko Speck later said he wasn't sorry for the twisted killings
Sicko Speck later said he wasn't sorry for the twisted killings

Speck also boasted about the amount of strength he needed to strangle someone.

He said: "It's not like TV... it takes over three minutes and you have to have a lot of strength."

Speck died of a heart attack, like his dad, one day before his 50th birthday.

The crazed killer doesn't even have a resting place because his sister feared it would be vandalised to the point of embarrassment.

His ashes were scattered in a secret location.

No one has ever looked for them.

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