Specific laws against locking main entrance gate of residential building

Is there any law against locking the main entrance of a residential building? One of the residents in our building, in collusion with some others on the 1st floor, locks the main gate of the building every night (sometimes around 9:30 - 10:00 pm) and does not open the same until about 7:30-8:00 in the morning. Although we have been given a key to the same, it is quite difficult for us to go down to the ground floor from the 4th floor everyday, to open the gate for our maid servant/housekeeper to come in. Also, sometimes when guests come a little late into the night (say after 10:00 pm), we have to go to the ground floor to open the gates for them. The miscreant does not cooperate even when the guest asks for the key from them.