According to the complaint lodged by the NPA officials yesterday, the first incident took place on January 23 when some unknown person pelted stones at the complex from outside the perimeter wall adjoining Hassannagar, a police officer said.
"Window glass of store room on the first floor was shattered," said Sub-Inspector G Narender of Rajendranagar police station.
A similar incident happened again on January 25 where window glass of a toilet block was broken and some marbles were recovered from the spot.
"Today we carried out searches in the houses of suspects in the surrounding area. The residents claim a boy was using a catapult. We are probing further," he said.