Kerala IEDs likely triggered with phone signal

The bombs used in the attack on a Jehovah Witnesses congregation in Ernakulam, Kerala were radio frequency-activated improvised explosive devices (IEDs) packed with low-grade explosives and petrol pouches. The IEDs were triggered by a radio-frequency based mechanism, possibly a mobile phone signal. It is believed that the bomber was not far from the site at the time of the blasts. The IEDs were packed in jute bags and placed under separate chairs covered with cloth to maximize the incendiary effect. The nature and composition of the IEDs suggest that the bomber was an amateur who learned how to assemble them from the internet.