"We would really like to know where such people find the arrogance to issue threats. We are interested in the context and background of those who might be behind this arrogance of his," government spokesman Ratko Macek told Hina by telephone.
Macek was commenting on a statement made by Petrac outside a court in the Greek town of Igoumenitsa, where he was arrested on Wednesday on an international warrant.
"I would like to say good, good luck to my Prime Minister Sanader in his political suicide," Reuters quoted Petrac as saying.
Croatian Interior Minister Ivica Kirin said that the police would investigate "all the circumstances of Petrac's statement".
"This government is doing all in its power to prevent threats being issued to ordinary citizens, journalists, public figures or members of the government. We will follow this plan through and put an end to organised crime and protect the legal system of the Republic of Croatia," Kirin said.
Petrac's Greek lawyer Alexis Kougias has announced that he will request that his client be tried in Greece, saying that Petrac fully qualifies for obtaining an asylum in Greece because a politically-motivate warrant has been issued for his arrest, the Croatian RTL Television network said on Thursday.
"(Petrac) is being prosecuted for refusing to reveal the whereabouts of (fugitive Croatian general Ante) Gotovina," Kougias told the judge in Igoumenitsa.