Zagreb - Croatian police have arrested 10 people suspected of taking part in the killing of journalist Ivo Pukanic, and were continuing the investigation with forces in neighbouring countries, a police spokesman said Thursday.

"They are dangerous members of the criminal milieu ... with the gravest crimes in their records," police spokesman Krunoslav Borovec told a press conference.

"We are continuing to collaborate with police in Serbia and Bosnia-Herzegovina," Borovec said. Two of the suspects are Serbian nationals.

Several of the arrested suspects were prominent figures from the powerful Balkan underworld, local reports said.

One of them, Robert Matanic, was tried in Bulgaria for 2004 gangland-style killings in Sofia, but was acquitted. Newspapers describe him as a hitman for organized crime across the Balkans.

Matanic's lawyer, Zoran Pilipovic, told the javno. hr portal that his client "did not commit the murder of Pukanic, but circumstances could connect him to it" and would "fully cooperate with the police department in charge of fighting organized crime.

He was arrested Wednesday afternoon on the Zagreb-Belgrade highway, near the border with Serbia, reports said.

Matanic had forged documents and was traveling with two Serbian underworld figures, one of whom has strong links with the reputed king of the southern European heroin trade, Sreten Jocic.

Pukanic, journalist, editor and publisher, was killed by an explosive device in central Zagreb a week ago. An executive of his publishing house, Frano Nikic, also died in the blast.

The double-murder, seen as an arrogant display of power by the Croatian underworld, came a few weeks after the brutal execution of a prominent lawyer's daughter, Ivana Hodak, a few weeks before.

The controversial Pukanic, whose sourcing and methods were both praised and disputed, reported on the billion-dollar businesses of cigarette, people, weapons and drugs trafficking.

Investigative reports by his Nacional weekly exposed links between organized crime groups in the entire Balkan area, that had survived wars and ethnic hostilities in the former Yugoslavia. (dpa)