Hazaribag: A day after a private bodyguard was shot dead by his colleague outside the office-cum-residence of Chatra SP Animesh Naithani on Tuesday, investigation has revealed that the key accused is out on bail after allegedly killing his four Central Industrial Security Force (CISF) colleagues in Bihar in 2017, police said.The deceased was identified as Atul Kumar, 30, a native of Buxar district in Bihar. Both the deceased and accused were deployed as private bodyguards of Belaganj MLA Manorama Yadav’s son and contractor Rocky Yadav alias Vineet Yadav. Rocky’s company is executing the Chatra bypass road project.Accused Balveer Singh, a native of Aligarh district in Uttar Pradesh, joined the CISF in 2008. On January 12, 2017, while posted at the Nabinagar Power Plant in Bihar’s Aurangabad district, he allegedly opened fire with his INSAS service rifle, killing head constable Bachcha Sharma, head constable Amarnath Mishra, constable Arvind Kumar, and assistant sub-inspector GS Ram. He was arrested, dismissed from service, and jailed in the case. But came out on bail. He reportedly joined a private security agency and was deployed as a guard, investigators said.Quoting family members of the accused, police said he had been under severe mental stress for years. He had earlier assaulted his wife with the butt of a rifle, causing serious injuries, and had once attempted to attack the driver of a passenger vehicle, they further alleged.Another line of inquiry involves a purported extortion letter, dated July 19, allegedly issued in the name of the Maoist central zonal committee. The letter reportedly demanded a five per cent extortion from contractor Rocky Yadav. Threatening “military action” in case of non-compliance, it allegedly warned that construction should remain suspended until the extortion amount was settled.The authenticity of the alleged Maoist letter is being verified. Also, investigation is under way if the extortion threat, the road project, and the shooting are connected, police added.Chatra SDPO Sunil Kumar said, “Police are probing all angles. Singh’s background, criminal history, employment records after bail, contacts, and recent movements are being scrutinised.”