An informant who helped break up an alleged plot to bomb a fuel pipeline feeding New York City's busiest airport was so convincing to the suspects that they actually thanked God he was with them, federal authorities said. The informant made several overseas trips to discuss the plot against John F. Kennedy International Airport, even visiting a radical Muslim group's compound in Trinidad, officials said. He also joined the plotters on airport surveillance trips - where authorities were waiting, they said. The suspects were convinced he was guided by a higher purpose: The ringleader believed the informant "had been sent by Allah to be the one" to pull off the bombing, according to a federal complaint. The four-person plot, revealed Saturday, demonstrated the growing importance of informants in the government's efforts to combat terrorism, particularly as smaller radical groups become more aggressive.