NEW DELHI, MAY 31: In one of the most sensational burglary attempts in the Capital, robbers broke into the high-security Border Security Force headquarters on May 21. Armed with a gas cylinder and other equipment, they managed to cut open a window grill on the 6th floor of the CGO complex building past midnight.When they were noticed by a sentry, they managed to escape. The complex also hosts CRPF, ITBP, CBI and an intelligence agency among others. The BSF headquarters shares a common terrace with the buildings of Staff Selection Commission and Central Industrial Security Force on either side.The burglary was detected by a BSF jawan on night duty. He saw some sparks and smoke coming out from the 6th floor, where documents concerning BSF's security arrangements are kept. The treasury is also on the same floor.The smoke was coming from room number 602 where files related to Jammu & Kashmir are kept. Usually there is no movement on the sixth floor during night, sources said.When the sentry raised an alarm, another jawan on night duty came to his help. By the time they reached the spot from which smoke was coming out, the burglars had escaped. No person or vehicle was seen fleeing from the road around the complex, sources said. The gas cylinder was discovered on the terrace of the building.Officials in the BSF said the burglary attempt failed and they have not lost any document or valuables.Senior BSF officials rushed to the spot after the burglary was detected. The police was informed and an FIR was lodged at the Lodhi Colony police station.Sources said high-level investigations are being made to ascertain the motive behind the burglary. BSF officials are carrying out an internal inquiry. ``There are two blocks here, Block 10 is BSF block and Block 11 hosts several other offices including that of Bureau of Police Research and Development. There are certain floors in both the blocks which are connected and there is no effective barrier in between,'' a senior BSF official said.``It is possible that they managed to sneak into the headquarters from Block number 11.