A leading member of the Sinaloa Cartel - who is accused of conducting twisted human experiments with fentanyl - has been arrested in Mexico, reportedly after being betrayed by his own men.

Néstor Isidro Pérez Salas, known as El Nini, was head of security for Los Chapitos - a faction of the Sinaloa Cartel led by the sons of infamous drug lord Joaquín 'El Chapo' Guzmán.

Mexican news outlets are reporting that El Nini was arrested by armed forces this afternoon (Wednesday, November 22) in Culiacan, a city in the state of Sinaloa. He is now set to be transferred to Mexico City and could face extradition to the US.

READ MORE: Mexico deploys 1,000 soldiers and Air Force jets to take on cartel after 'narco tank' attack

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Cartel boss who conducted human experiments 'could ditch El Chapo's sons and start drug war'
El Nini led a violent criminal cell and was head of security for Los Chapitos

A video has emerged purporting to show El Nini attempting to escape from authorities on the roof of a complex in Culiacan, all while guns are being fired. This last-ditch attempt to flee was unsuccessful.

Journalist Luis Chaparro cited US sources as saying it was El Nini's own people who "left him alone to be captured". El Nini was apparently "looking to create his own organisation" after losing support from Ivan Archivaldo Guzmán (one of El Chapo's sons). Just days ago, an expert suggested El Nini could be looking to betray Los Chapitos and go into business for himself.

The net has been closing around El Nini for some time now. Security forces raided his properties earlier this month (and bizarrely found three Bengal tigers).

It comes as part of a wider push for Los Chapitos to be brought to justice. They stand accused of flooding the US with deadly fentanyl, contributing to spirally overdose deaths, among a raft of other cartel-related crimes.

Ivan Archivaldo Guzmán (pictured) reportedly pulled support from El Nini before today's arrest
Ivan Archivaldo Guzmán (pictured) reportedly pulled support from El Nini before today's arrest

Ovidio Guzmán - one of the four sons who took over the Sinaloa Cartel after El Chapo's capture - was arrested earlier this year and is in US custody. Indictments were passed against several other members of the organisation including El Nini. US authorities were offering a $3million reward for information leading to El Nini's capture.

An indictment from the Southern District of New York previously described how El Nini and another Sinaloa Cartel operative known as El 27 used unwilling human beings as test subjects for their fentanyl, despite the fact "the cartel possesses the technical capability" to test its drugs in a laboratory.

El Nini could now face extradition to the US
El Nini could now face extradition to the US

The pair were said to have experimented on one woman they were "supposed to shoot", injecting her "repeatedly with a lower potency of fentanyl until she ultimately overdosed and died". They also tested fentanyl on "individuals who were tied down". The indictment went on to state that "three cooks in a fentanyl lab that they controlled died after sampling the product".

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