China: RCIEDs Discovered at High School

TRIPwire, 10 December 2019

On 9 December 2019 at approximately 1730 hours local time, the Hong Kong Police Force received reports that a janitor at a private high school discovered two radio-controlled IEDs (RCIEDs) at the school. The Hong Kong Police Force Explosive Ordnance Disposal Bureau rendered the devices safe without incident. The viable devices consisted of an estimated 22 lb of 2 types of explosives enhanced with fragmentation in the form of nails, with a potential range of 328 ft. The explosives used included a primary high explosive—hexamethylene triperoxide diamine (HMTD)—designed to act as the initiator and booster in the device, and the secondary incorporating ammonium nitrate. The device components were made with two sieves wrapped in plastic wrap, two mobile phones, and a battery holder containing three batteries, all connected to a circuit board. According to police, the devices were hidden at the school, but the location was not the intended target. Authorities have not linked the devices to the current political unrest in the region, but officers are looking into the association between the devices and a handgun recovered on 8 December. The investigation is ongoing.