Taxi drivers in Bulgaria's Sliven marched to protest against the murder of their colleague Zhivko Dimitrov.

Police confirmed information that Dimitrov was murdered. Several options were possible, police said. The murder could have resulted from a robbery attempt or could have been the work of drug addicts, Focus news agency reported.

Taxi drivers found Dimitrov's body on the morning of December 4. A knife was thrown close to the body.

Nearly 250 taxi drivers joined the search for the man, who went missing on January 3.

Police representative Hristo Grigorov said that the large number of people that joined the search could have resulted in the destruction of some evidence.

Sliven taxi drivers said that incidents occurred often but the murder was unprecedented. Grigorov said that the problem was aggravated by the fact that drivers rarely told police officers of such occurrences.

Dimitrov called the company he worked for when he was 18km away from Sliven and traveling. The man complained of fog. Soon after he went missing.

The car was found on January 3. It was set on fire, Focus reported.