Akhir 07, 1432 H/March 12, 2011, SPA -- Former Serbian prime minister Vojislav Kostunica on Saturday accused the authorities of political persecution over plans to question him over the assassination of one of his predecessors, according to dpa. Kostunica was responding to media reports quoting prosecution sources as saying he would be interrogated about the political background of reformist Zoran Djindjic's slaying in March 2003. "I have nothing to do with the political background to Zoran Djindjic's killing and neither does the Democratic Party of Serbia (DSS)," he told a press conference. Kostunica served as premier between 2003- 2008, and is now in opposition. A group of rogue policemen and organized crime heads was sentenced to long terms in prison for killing Djindjic, but the verdicts have shed no light on the political support they may have had. Kostunica's political foes say that he, at the time president of rump Yugoslavia, at least encouraged the killers by siding with the shadowy police commando unit opposed to Djindjic a prior to the assassination. Now, he said, the prosecutor's office is being "misused" to launch a "political process ... (in a) campaign against DSS." He said he has already told everything he had to tell about the killing and that he will not respond to summons for the interrogation. "The prosecution knows that there is no grounds to interrogate me," he added.