Sofia - A writer exposing Bulgarian underworld bosses was shot in the head in Sofia Monday, hours after a prominent businessman was killed in an apparent professional hit, local reports said.

Georgi Stoev was critically wounded in cental Sofia by one or two attackers, who fled the scene, the novinite. com news site said. No other details of his condition were immediately available.

Stoev was reportedly conducting interviews, gathering material for his next book on organized crime.

The news of the attack broke just hours after that of the murder of the head of Atomenergoremont, a company which maintains the reactors in Bulgaria's nuclear power plant Kosloduy.

The victim, Borislav Georgiev, 41, was killed Sunday evening in his apartment building in Sofia with two shots to the head. The killers got away.

Dozens of people including businessmen, public officials, as well as common thugs have been killed in Bulgaria in underworld wars in recent years.

Bulgaria joined the European Union in 2007 despite shortcomings in its combat with powerful organized crime, which earns many millions of dollars each year from the smuggling of narcotics from the East to Europe alone.