Bulgaria's Prosecutor-General Boris Velchev will ask Parliament to lift the immunity from prosecution on Roumen Petkov, the former interior minister who resigned last month after a protracted row caused by allegations of corruption among top police personnel.

The request comes as a result of the probe into information leaks at the ministry, launched by Sofia prosecutors last week, Velchev told a seminar organised by corruption watchdog Transparency International in Sofia on May 19, as quoted by Dnevnik daily.

After resigning as minister, Petkov returned to Parliament as MP, which means that he can only be investigated if the legislature lifts his immunity.

One of the leaks investigated by prosecutors involved the information received by Bulgarian media concerning anonymous records of phone calls in which Ivan Ivanov, deputy head of the ministry’s chief directorate for combating organised crime (CDCOC), discussed ongoing investigations. The records were part of the ministry’s investigation into Ivanov, who was arrested a day later, on March 18.

In another case, Iliya Iliev, former chief secretary of the ministry, who was arrested on March 25, could be indicted for allegedly taking a CD with classified information when he resigned in December.

The third case was the disclosure of the fact that controversial businessman Alexei Petrov was a secret agent of the ministry, which is the instance that could lead to Petkov's indictment.

Petrov's name surfaced in the media after former CDCOC head Vanyo Tanov told Parliament that Petrov had arranged a meeting between former interior minister Roumen Petkov and controversial businessmen Plamen Galev and Angel Hristov in 2006. Tanov said that at the time of the meeting, Galev and Hristov were the targets of a police investigation. Petkov later confirmed Tanov’s words, but accused him of blowing Alexei Petrov’s cover as a secret collaborator of the ministry.

Petkov re-iterated on May 19 that he was ready to give up his immunity from prosecution. Two days earlier, he was quoted by Focus news agency as saying that the investigation against him was "the result of lies and slander from people who, mildly put, have a questionable authority among professionals", indirectly referring to opposition MP Atanas Atanassov, one of Petkov's harshest critics and a former chief of Bulgaria's intelligence service.