In 1978, U.S. Congressman Leo Ryan went to Jonestown to investigate supposed abuses by the People's Temple onto its members. After staying for a day, Ryan tried to leave, taking four of the cult members who had decided to defect. Realizing this, Jones ordered them killed, as was done. Sensing that his utopia in the jungle would surely come to an end after word got back to the states about Ryan; Jones decide to put his suicide plan into action. Telling his subjects that it was a "revolutionary death," he had a large quantity of fruit punch laced with cyanide prepared. After making all 276 children at Jonestown drink the punch, all the adults proceeded. In the end, after Jones apparently killed himself with a gunshot to the head, 914 people had died.
http://www.owlnet.rice.edu/~reli291/Jon ... stown.html