Police have arrested former prisoner Ivan Radev, known as "Monkata", in the village of Chokoba. He is a suspect in the knife killing of a young man in Sliven. Officers from a specialist police unit detained him within hours of the attack.

The young man died on Wednesday, 4 November. Unofficial reports of a detained suspect appeared the same day, but neither police nor prosecutors confirmed them.

Where it began: Suspect in Sliven stabbing detained, unconfirmed reports say

Armed, hooded officers in uniform escorted Radev to the police building in Sliven.

The two men knew each other. Early reports say an argument turned into a fight, and one of them pulled a knife, struck the other with fatal blows and left. The first unconfirmed accounts named a petrol station in the Druzhba district, but later ones place it in the town's villa zone.

As soon as police got the alert, patrols took up positions at the exits of Sliven and began stopping cars to search them. Residents who posted on social media said officers looked inside car boots, back seats and the cargo areas of vans and pickups. They said the aim was to stop the suspect from hiding or leaving the area.

The motive for the killing is not known. Police still have to establish what started the row, what exactly happened between the two men and what evidence points to the man in custody.

Radev is known from crime reports. Nine years ago he was serving a six-year sentence in Burgas prison for kidnapping a drug dealer. On camera, he said he had sold methamphetamine to inmates there for more than three years. He said the drug got in with the help and protection of prison staff, and some of the profits went to officials in charge of order and security. His claims caused a public scandal and an investigation.

Radev's relatives say he came under pressure afterwards. They say people tried to persuade him to sign papers moving him to the psychiatric ward of the prison hospital in Lovech.