One of the weapons probably used in the murder of rationalist Narendra Dabholkar five years ago was not destroyed by the alleged killers as they believed it was "lucky" for them, CBI sources said. The weapon could have also been used in the murder of other left leaning activists like Govind Pansare in February 2015, M M Kalburgi in August 2015, and Gauri Lankesh in September last year, they said, however, adding with caution that any conclusion can only be drawn after a confirmatory ballistic test of the firearm. The agency has recently arrested and questioned Aurangabad-resident Sachin Andure who is alleged to be one of the two shooters involved in the killing of Dabholkar on August 20, 2013, in Pune while on his morning walk, they said. A country-made pistol was also recovered from a friend of his relative by the CBI which is believed to be one of the weapons used in the murder, they said. The CBI will send the weapon for ballistic tests to ascertain the claims of Andure before reaching any conclusions in the case as the investigators believe that his claims cannot be taken on face value, they said. During the questioning, Andure has claimed that the right wing militant group believed to be behind the killings had over a dozen of such weapons to execute their nefarious plans. When asked why this particular pistol which he is claiming to have been used in the killing of Dabholkar was not destroyed even after five years, he indicated that it was a "lucky" weapon used in different killings. The agency now wants to question alleged killers involved in the murder of noted writer and journalist Gauri Lankesh, they said, adding that it is also seeking custody of Sharad Kalaskar, arrested by the Maharashtra ATS. Kalaskar was arrested during an operation of the ATS to bust a right wing extremist module plan to carry out multiple attacks on the occasion of Independence Day. After the arrests, the ATS had claimed that it had seized a huge cache of explosive materials and country-made firearms during raids at various places in the state. It was during the interrogation of Kalaskar that lead about involvement of Andure in Dabholkar killing surfaced. This input was passed on to the CBI which had arrested Andure from Maharashtra. The CBI has a strong theory that killings of journalist Gauri Lankesh, Govind Pansare, M M Kalburgi and Narendra Dabholkar could be linked as modus operandi and ammunition used in the murders is similar, they said. The CBI is probing the murder of Dabholkar while that of Pansare, Kalburgi and Lankesh are being investigated by state agencies of Maharashtra and Karnataka.