"We found there is a weak link in the security system of the said station (Chandani Chowk). This weak link or to say structural deficiency has been in the notice for sometime. The Intelligence Bureau had done an audit of Metro stations and it was mentioned in their report and CISF too has mentioned about this existing flaw to Metro authorities more than one time in writing.
Singh, whose force is responsible to secure the Metro network and its passengers, said it was by taking the "advantage" of this weak link that 22-year-old Shivesh Kumar was able to smuggle in a bag, containing the said weapon, by easily hoodwinking security personnel last week.
He is later alleged to have used the gun to shoot himself grievously after he got down at the Rajiv Chowk Metro Station.
The Central Industrial Security Force chief said the bag was handed over to Kumar by his sister from over a 3-feet glass partition which is located in the unsecured area of the Chandani Chowk station.
The October 1 incident brought to light the vulnerability of some heavy footfall receiving stations of the rapid transport system of the national capital region which receives an estimated 26 lakh passengers each day.
Singh said the force will also enhance the number of its personnel on this system keeping in mind security requirements.