Berlin, Rabi Al-Awwal 28, 1432 H/March 3, 2011, SPA -- German prosecutors are to conduct a formal investigation into plagiarism allegations against former defence minister Karl-Theodor zu Guttenberg, they announced Thursday, dpa reported. Earlier in the day, Guttenberg was formally relieved of all ministerial and parliamentary duties after he proffered his resignation Tuesday, following revelations that he had copied large sections of his PhD thesis without citation. State prosecutor Reiner Laib said the investigation "will be initiated, there are no ifs and buts." He said it could take a while to gather all the necessary material to assess charges relating to Guttenberg's 475-page thesis, more than 100 pages of which allegedly contain plagiarisms. "Of course the investigation has advanced quite far," Laib told German Press Agency dpa. Just over two weeks have passed since the plagiarism allegations first surfaced. Contributors to a website have scrupulously worked through Guttenberg's thesis - on US and EU constitutional issues - to spot passages lifted from previous published works. The former minister, of Bavaria's Christian Social Union, admitted to having made "grave errors" in his doctoral thesis. Bayreuth University then stripped Guttenberg of his doctoral title - at his own behest - but this was not enough to quell demands that he step down, spearheaded by the academic community. The 39-year-old could face judicial proceedings over copyright infringement and breach of trust, as he has also been accused of using the services of academic researchers in Germany's lower house of parliament for private purposes - to provide material for the thesis. Guttenberg's renunciation of his parliamentary duties will ease the judicial process against him, as legislators enjoy parliamentary immunity during their time in office. If found guilty, Guttenberg could potentially face both a fine and jail time. -- SPA 19:57 LOCAL TIME 16:57 GMT www.spa.gov.sa/870098