Presenting his defence before the Zagreb County Court last week, Mafalani said that he had told Sipusic, whom he had known from before, that a murder was about to happen. Mafalani allegedly asked to talk to Sipusic after the first defendant in the trial, Robert Matanic, had threatened to kill him.

Sipusic told the court on Monday that Mafalani had told him that "something big is about to happen downtown", but that he had not told him where it would happen, who was about to killed or by whom.

"The information he gave me was insufficient to come to any conclusion or take any action," Sipusic said.

He added that he had advised Mafalani to stay in touch with Matanic whom he had described as his source.

Asked by the judge why he had not reported this to the police, especially in light of the fact that several days earlier legal trainee Ivana Hodak was killed in downtown Zagreb, Sipusic said that there was an instruction for police not to submit generalised reports.

He said that Mafalani contacted him by cell phone, that his cell phone was registered in his name, which was why he knew that his name too would crop up during the investigation.

The police talked to Sipusic only a month or two after Pukanic's murder.

Apart from Sipusic, the court will also hear testimonies of other police officers Mafalani mentioned while presenting his defence.

Pukanic and his business associate Niko Franjic were killed in the explosion of a bomb attached to a scooter parked by Pukanic's car outside the Nacional building in Zagreb on 23 October 2008. Franjic was a collateral victim.

Robert Matanic, Luka Matanic, Amir Mafalani, Slobodan Djurovic and Bojan Guduric are standing trial for this crime in Zagreb.

Sreten Jocic, Zeljko Milovanovic and Milenko Kuzmanovic, also indicted in this case, are standing trial before a Belgrade court.