Calcutta, June 21: Burglars broke into several offices on the seventh floor of Marshall House on Strand Road last night and left with over Rs 60,000 and a laptop among other items.

When the employees of the various firms came to work this morning, they found the main door locks either broken or tampered with.

Police said seven offices were raided and three of them were looted. The break-in bids on the others were futile.

But members of the Marshall House Owners’ Society claimed the thieves had tried to break into at least 14 offices, those of share brokers, chartered accounting firms and small manufacturing units.

The two guards on duty — Ram Prasad Rana and Ganesh Singh, in their mid-50s and working in the building for years — have been detained.

“With the entry gates to the three staircases closed and the four lifts shut down after 8pm, it is difficult to reach the seventh floor minus inside help,” said Dilip Chaudhury, the secretary of the society.

“There are seven guards who work in shifts apart from the durwans. Although the society pays them, we don’t have much control as all of them are members of unions. Almost every night some people are allowed to sleep inside the building and you can’t do much,” said S.K. Gupta, a former president of the society.

A chisel and a screwdriver were found inside the Agarwal Trading office. The police said they were probably used to break open the locks. Footprints were found on chairs inside room No. 703, the office of Beriwala Hardware.

Some of the office owners blocked Strand Road around 3.30pm, demanding greater police vigil in the area.