A note found at the site where two U.S. missionaries were kidnapped said drug traffickers will kill them if Colombians are extradited to the United States to face drug charges, an official said.

The missionaries, kidnapped Tuesday night, had received threats and knew they lived in a dangerous area, a relative in the United States said Friday.Hector Pardo, spokesman for the Colombian Evangelical Federations, said the missionaries - Richard Grover, 50, of Warroad, Minn., and Roy Libby, 50, of Atlanta - were being held by drug traffickers who threatened to kill one of them for every Colombian extradited to the United States to face drug charges.