(CNN)A man who had oversight over a web of assassins working for the infamous drug trafficker Pablo Escobar is dead.
Jhon Jairo Velásquez, also known as "Popeye," died on February 6 at the National Institute of Cancer in Bogotá, Colombia, the National Penitentiary and Prison Institute (INPEC) said in a statement.
Velásquez had been hospitalized there since December 31, where he received treatment for stomach cancer.
"Popeye" was known as one of Escobar's most dreaded hit men. He has confessed to killing upwards of 300 people in Colombia during his time working for Escobar's cartel.
His history with Colombian authorities
Velásquez had served 23 years in prison for drug trafficking before authorities released him in August 2014, but he was arrested again in May 2018 and charged with extortion.
The Colombian Attorney General's Office had opened an investigation against him after he repeatedly threatened Colombian presidential candidate Gustavo Petro and his followers.
And in December 2017, authorities found Velásquez at a luxurious birthday party of drug trafficker Juan Carlos Mesa Vallejo, also known as "Tom."
Vallejo had been a drug trafficker for 30 years, and had accumulated a fortune almost as large as Pablo Escobar's. The Prosecutor's Office said Velásquez revoked his probation. Velásquez said otherwise.
"It was a birthday party. In a hotel. I was at that hotel. In the wrong place. It's not a crime to go to a party. That's why they released me," he said on Twitter.
These events led to his arrest in May 2018.
Translation by Francisco Guzman