Kanpur (Uttar Pradesh), June 20 : The Kanpur police have invoked the stringent National Security Act (NSA) against Shivam Dubey, an aide of slain gangster Vikas Dubey. Shivam, along with the gangster, was allegedly involved in the Bikru massacre in which eight police personnel were shot dead on July 3 last year, when they had gone to arrest the gangster. Under the NSA, a person can be detained without a charge for up to 12 months if the authorities feel he or she is a threat to national security or law and order. "Shivam, who was booked under sections 147, 148, 149, 302, 307, 394, 120 b of IPC and 7 CLA Act and 3/25 Arms Act with regard to Bikru shootout on July 3 night, was arrested by Special Task Force on July 23 from near a detergent factory in Chaubeypur," said the police. Additional Superintendent of Police (ASP), STF, Vishal Vikram Singh had then stated Shivam was present on the day of the ambush as per electronic evidence and also the statements given by other members of the gang arrested earlier. Shivam had also taken shelter at his maternal aunt's place in Hardoi. The double-barrel gun used by him to attack the policemen was also seized from his possession. Additional Director General (ADG) Bhanu Bhaskar said, "District Magistrate (Kanpur Nagar) has ordered slapping the National Security Act against Shivam Dubey, one of the accused in the Bikru massacre case." Shivam, a cousin of Vikas, was a very close aide of the latter. He used to look after fish ponds of the slain gangster in the village. Vikas was killed in an encounter in the morning of July 10, when a police vehicle carrying him from Ujjain to Kanpur met with an accident and he tried to escape from the spot in the Bhauti area in Sachendi, the police had said. Prior to Dubey's encounter, five of his alleged associates were killed in separate encounters, while 36 including two policemen and four women were arrested and sent to jail. /IANS