Guwahati, June 14 : Chandra Kumar Nath, husband of Assam woman BJP leader Junali Nath whose body was found on road in Assam's Goalpara district, has filed an FIR against CID IGP Debaraj Upadhyay, alleging a "doubtful" investigative report by the police. According to a complaint lodged by Chandra Kumar on Tuesday evening, "The narrative of the case has been changed by CID. How the accused killed the victim while operating a vehicle was left unexplained by the investigation report, it said. "The police's extramarital affair angle of the case is unacceptable and Junali Nath's character is unquestionable," Chandra Kumar said. "We have experienced great stress as a result of the inconvenient probe," Chandra Kumar claimed. Junali's family has sought an apology from the police by calling for the retraction of the news release and launch of a thorough investigation to identify the culprit. Earlier, on Tuesday, the police claimed that Junali was murdered by her lover Hasanur Islam. Islam was detained by police on Monday evening, and Assam's CID said that for more than two years, Nath had an affair with Islam. Upadhyay told the press that Islam had admitted during police interrogation of having an affair with Junali for more than two years. Islam said that as he married another woman, Junali was upset, Upadhyay had told the press. Islam said on Sunday night when Junali came to meet him, he picked her up in his car at the Matia area of the Goalpara, after which quarrel began inside the car, Upadhyay added. "Islam hit her many times on the face when she was questioning his marriage, rendering her unconscious," the officer said. After post-mortem, doctors said that a heavy object was used to kill Junali, but Islam informed the police that he hit Junali in the face until she passed out. "When Islam realised Junali was dead, he abandoned her near the road and drove off. He also banged her head on the hard portion of the automobile. The car had bloodstains on it, and we have found it," Upadhyay added. /IANS