Bhubaneswar, May 26 : The Odisha crime branch on Friday filed a more than 540 pages charge sheet in the murder case of the then health minister Naba Kishore Das. In a press statement, the crime branch said it has filed the charge sheet in the court of SDJM, Jharsuguda against accused Gopal Krishna Das (53) for murdering the then health minister on January 29 and attempting to kill others, including inspector in-charge of Brajrajnagar police station, P. K. Swain and another Jeevan Kumar Nayak. The crime branch said that the accused Gopal Krishan Das (the then police ASI) committed the crime in his senses and in a pre-planned manner. His mental condition was found stable and normal, it said. "After evaluation of all the evidence-oral, documentary, medico legal, cyber forensic and ballistic opinion, it became clear that accused Das had developed personal grudge and anguish against deceased minister Naba Kishore Das. He felt threatened from Das and his supporters and feared for his life. Gradually, he made up his mind to commit his murder. For this he meticulously planned and then executed the crime," the CB said. Though the charge sheet was filed, the investigation is kept open in respect of obtaining a few reports and clarification and for complying with some formalities, it said. As the matter involved an attack on the life of a serving minister, the crime branch took charge of investigation of Brajarajnagar P.S on the very day of the incident (January 29). The crime branch had formed 10 investigating teams and deputed to Jharsuguda, Bhubaneswar, Berhampur and other places even beyond the state to probe into different possible angles of the case. The teams examined 89 witnesses and seized several exhibits, including firearms, live cartridges, empty cartridges, hand wash of the accused etc. During investigation, some family members of the accused claimed that Gopal Das was suffering from bipolar disorder long back. To verify the authenticity of the claim, a special medical board was constituted by the director of medical education and training, who conducted their examination and opined that they had not found active psychopathology in Das. Further from locals and colleagues, it was also ascertained that his mental condition was quite normal and there was no abnormality. Moreover, he was cooperative in the investigation and replying to all the questions asked in a cogent manner, the CB officials said. Notably, the then police ASI Gopal Das had murdered the then health minister Naba Das using his office revolver. Oppositional parties in the state had alleged conspiracy behind the murder. However, the crime branch probe has not found any conspiracy angle. /IANS