On 5 December 2001, pirates shot and killed Blake while he was on an environmental exploration trip in South America, monitoring global warming and pollution for the United Nations. The two-month expedition was anchored off Macapá, Brazil, at the mouth of the Amazon delta, waiting to clear customs after a trip up the Amazon river. At around 9 p.m. a group of six to eight armed, masked robbers wearing balaclavas and crash helmets boarded the "Seamaster". As one of the robbers held a gun to the head of a crewmember, Blake sprang from the cabin wielding a rifle. He shot one of the assailants in the hand before the rifle malfunctioned; he was then fatally shot in the back by assailant Ricardo Colares Tavares. The boarders injured two other crew members with knives, and the remaining seven were unhurt.