James Warren "Jim" Jones (May 13, 1931 – November 18, 1978) was the American founder of the Peoples Temple, which became synonymous with mass suicide after the November 18, 1978 death of over 900 people from cyanide poisoning in their isolated agricultural intentional community called Jonestown, along with the death of 9 other people at a nearby airstrip and in Georgetown. To the extent the actions in Jonestown were viewed as a mass suicide, it is one of the largest such mass suicides in history, perhaps the largest in over 1,900 years and the greatest single loss of American civilian life in a non-natural disaster until the incidents of September 11, 2001.
There was a recording of the mass suicide and I'm pretty sure that's where the clips you hear in song came from.
http://http://en.wikipedia.org/wiki/Jim_Jones