An explosive device went off in an apartment building in Sofia's Strelbishte residential district on the morning of January 16.

Police received a call at 5.20am, an Interior Ministry press release said. The explosion caused damages to the building.

None of the residents were harmed.

The device was placed close to the apartment of a 35-year old man, having past criminal record. Police investigated the man for theft, evidence concealment and property destruction.

In 2002 the same man found an explosive device in front of his apartment.

Police said that the number of similar crimes has been going down over the past years. In 2002 police worked on more than 40 explosion cases. The number went down to 24 in 2003 and to 12 in 2005, Focus news agency reported.