Bulgaria's anti-mafia police unit has captured 8 kg of heroin hidden in the exhaust pipe of a car in a special operation near the city of Stara Zagora.

The drugs were found in a car that crossed into Bulgaria from Turkey on Thursday through the Lesovo border crossing point, the Interior Ministry said Friday.

The police have arrested the driver of the car, Stoyko Chernakov, a 22-year-old male from the village of Tulovo near Stara Zagora, as well as 58-year-old Boris Dimitrov from Stara Zagora, 28-year-old Nedelcho Minchev from Stara Zagora, and 51-year-old Veselin Valchev.

According to the estimates of the Bulgarian investigators the 8 kg of heroin are worth about BGN 1 M.

One of the detainees, Boris Dimitrov, was arrested back in 2007 with 29 kg of heroin, and was sentenced to 4.5 years, Stara Zagora police commissar Alexi Aleksiev reminded, as cited by BGNES.

Nedelcho Minchev also has a criminal record for drug trafficking; according to the police, he and Dimitrov probably got acquainted in jail from where both were released before the end of their sentence terms in 2010.

According to commissar Aleksiev, Boris Dimitrov is a "solo player" on the Bulgarian drug market who managed to become established regardless of the big Bulgarian mafia groups.