Three more cars were set on fire Tuesday into Wednesday in the capital Sofia, the central town of Kazanlak, and the Black Sea city of Burgas.

The one in Sofia burned around midnight in the Sofia "Mladost" district, where the most arsons have been registered so far. The automobile had title plates registered in the northern city of Montana.

In Kazanlak, the car was set on fire just 50 meters from the regional police precinct. With it, the number of vehicle arsons in the Stara Zagora region where Kazanlak is located reached 5 in the last 14 days.

In the wee hours Wednesday, a car was set on fire in Burgas, in the city's downtown.

There had been over 60 such incidents in Bulgaria in the last month and a half, with 20 of them outside the capital.

Police say that the arsons were committed by several groups with different motives and some have been copycat criminal actions. Others believe the arsons were set on purpose by an unknown, but powerful mastermind in order to destabilize the cabinet of the ruling GERB.

Ivan Kamenov, the fourth suspect regarding the recent series of car arsons in Bulgaria's capital Sofia, will remain in custody, the Sofia District Court ruled Sunday.

The court believes that Kamenov is likely to hide or commit other crimes if he is released. The suspect has had a previous sentence for arson.

Kamenov has been accused of torching a vehicle in Sofia's Lyulin residential district. His lawyers have pointed out that the witnesses who have implicated him in the crime have criminal records or have been under the influence of cannabis, which would make their accounts doubtful.

Ivan Kamenov is the fourth suspect for the notorious series of car arsons that began at the end of November

On December 27, the Sofia Appellate Court released Yuliyan Kovachki , 29, on own recognizance. Kovachki was allegedly responsible for several arsons that took place in the Mladost residential district.

Several days earlier, another suspect, 33-year-old Vladislav Nikolov AKA Kukata (The Hook) was also released on own recognizance. On December 20, suspect Radoslav Stoyanov was released on a BGN 1700 bail.