The idea of ​​an online homicide market was conceived in the mid 90's.
In 1994, Timothy C. May, electronic engineer and ideologist of crypto-anarchism, wrote a document called Cypheronomicon in which he described the Assassination Market that would allow anyone to place a bet on the exact date of death of a famous person. This system exploits the ability to "guess" the date of death of a character, as proof of the murder of the individual in question.
Or if you managed to predict exactly the death of a person, it means that it was you who killed him.

Jim Bell (Intel engineer) instead imagined a platform where users could nominate (anonymously) someone to kill in exchange for money. People would also have had to pay a small fee to make a "prediction" with an encrypted message that only the predictor and the site knew about when that person was going to be killed. Once that person was confirmed dead, the predictions would be deciphered and the promised funds would automatically be transferred to the successful predictor.

DARK WEB
Thanks to these ideas, the unknown Kuwabatake Sanjuro created in 2013 on TOR a platform where anyone could place a bounty on a public figure in a completely anonymous way, using Bitcoin.
The platform in question was called Assassination Market.
But how did it work? The site indicated names of politicians, industrialists and other prominent personalities, flanked by a Bitcoin bounty.
They ranged from the 10 Bitcoins offered for the head of NSA director Keith Alexander to $ 28,000 for Barack Obama's, up to $ 86,000 for Ben Bernanke (head of the Federal Reserve Bank).

YURA SITES
Camorra Hitmen, Besa Mafia, Crimebay, Cosa Nostra International Network, Azerbaijani Eagles and Hitmen are all markets created by a certain "Yura". But how do they work? Users select the type of violence, upload the photo and address of the designated target and wait to receive news from the messaging system. Users have often asked Yura questions: how do I know you're real? Can you make it look like an accident?
The user then transfers the agreed sum into a wallet on the site, where they will apparently be kept safe until the work is completed. Instead, Yura takes the money immediately, without even starting the job.
The user complains, Yura says he needs more money to hire a better hit man; the user pays again or asks for a refund; Yura disappears or attempts to extort the user by threatening to hand over information to the authorities.

One of the first known cases was that of Alexis Stern (a 20-year-old woman) who was told by the police that someone wanted to have her killed.
The killer (his ex) had connected to Camorra Hitmen to commit the action. The nickname was "Mastermind365" and he sent the site administrators a photo of him and $ 5,000 in BTC in exchange for his kidnapping, later changed to murder.
The girl alerted by the police began a self-defense course, often walking around with a knife and pepper spray.
Security cameras were also installed in his home.
The murder was never carried out.

In February 2016, a user had logged in with the nickname "dogdaygod" by ordering a murder on a middle-aged woman who lived in Cottage Grove, Minnesota.
The target was a dog trainer called Amy Allwine.
Dogdaygod transferred over $ 6,000 to Yura and gave him some dates when Allwine would be out of town on business and when she would be alone at home without her husband, Stephen.
Dogdaygod and Yura first discussed the orchestration of a hit-and-run made to look like an accident, then a murder followed by an arson attack.
Over time, however, the "hit men" continued to fail.
Following a Hacking attack, a lot of information was extracted from Yura's databases.
The FBI examined the handful of targets found in the database by visiting the Allwines home and informing them that someone was premeditating a murder against Amy.
The agents suggested to the Allwines to strengthen security and then left. Amy and Stephen installed a home security system by buying a gun.
Six months later, Stephen shot Amy in the head.
Because?
Well Stephen Allwine was dogdaygod; he was arranging business through the Ashley Madison infidelity site but could not consider divorce because of his position in the church. He had taken out a wife's life insurance policy of $ 700,000 and sent her threats and exhortations to kill herself (through various online aliases).

One confirmed murder case was that of Bryan Njoroge (Indiana, USA) made it look like suicide (in fact someone had paid $ 5,500 in Bitcoin to order his murder).

According to an investigation, about ten people have been arrested for attempted murder.
As said the Yura sites are 90% SCAM, however many people have applied to become an assassin.
Yura has always asked them for a test: burn a car, make a video and upload it to the web.
There are many videos where you can see masked people setting fire to cars (with sheets with "Besa Mafia" written on them).

Here a video of burning car: https://www.youtube.com/watch?v=KILUsa4crzI