Serbian police have arrested a pop signer for her alleged involvement in the killing of Prime Minister Zoran Djindjic last week. The young woman, Svetlana "Ceca" Raznatovic, is also the widow of a feared warlord, who was killed in a gangland style attack in 2000. The woman who became famous in Serbia with songs such as "evidence" is now herself detained as part of a criminal investigation.

Police say they have proof that Serbian pop star Svetlana Raznatovic, known as "Ceca," sheltered key leaders of the Zemun Clan, which the authorities have blamed for Wednesday's assassination of Prime Minister Zoran Djindjic. The 50-year old Mr. Djindjic was shot and killed in front of a Belgrade government building, in an apparent retaliation for his crackdown on organized crime.

Serbia's parliament was expected to elect 42-year old former Yugoslav Interior Minister, Zoran Zivkovic, as his successor on Tuesday.

Pop star Ceca's alleged close ties to the underworld did not came as a surprise. She was married to crime boss and warlord Zoran Raznatovic, also called 'Arkan,' who was killed by mobsters in the lobby of Belgrade's Inter-Continental Hotel in 2000. Arkan was wanted for war crimes by the U.N. Tribunal in The Hague, because his paramilitary troops were alleged to have committed atrocities during the Balkan wars of the 1990s.

The arrest of singer Ceca, whose home was raided Monday, was expected to come as a shock for her fans. More than 70,000 people are said to have attended a concert last June devoted to her late husband in a Belgrade soccer stadium.

More than 300 people have been reportedly arrested so far in the investigation of Mr. Djinjic's assassination. But officials say that several ringleaders remain at large, including Zemun chief Milorad Lukovic, a paramilitary commander and state security chief under President Slobodan Milosevic.

On the political front, the federal parliament approved a five-member cabinet to lead the new federation of Serbia and Montenegro that replaced Yugoslavia earlier this year. The government, will be chaired by Montenegrin Svetozar Marovic, and will deal mainly with foreign affairs, defense, economy and human rights.