 It remains unclear what provoked the attack, but various proposals have been put forward, including increasing threats by drug traffickers and loggers and unusually cold weather related to recent climate change.The rubber boom in the Las Piedras River ended around 1912, but in recent decades the Las Piedras has been host to other forms of resource extraction, including oil prospecting, several timber booms, and the paving of the nearby Interoceanic Highway.In 1996, the Mobil Oil was granted a 1,500,0000 ha concession to prospect for oil.