Police were called to an industrial building in Tai Kok Tsui Wednesday night after a security guard found a batch of suspected rifles. The call came in at around 7 pm after a security guard spotted the firearms near a dumpster on the ground level of the On Yip Factory Building on 33 Ivy Street. Officers found 13 firearms, suspected to be air rifles and around 100 rounds of ammunition that had been dumped at the scene. Police located a unit inside the building suspected to be connected with the case after midnight and took away a wooden box, a piece of luggage, and several Styrofoam boxes to help with the investigation. Sources said the unit was under renovation, and the construction workers had dumped the firearms earlier while clearing out the unit.