As many as a dozen people with suspected connections to al Qaeda were plotting to explode bombs on U.S. soil, say authorities gathering evidence for an indictment against Najibullah Zazi, the Afghan immigrant airport shuttle driver from Aurora who is at the center of an international terrorism investigation. That's according to the Chicago Tribune , which cites several officials who believe more serious charges will be filed against Zazi. Zazi could be charged with providing material support to terrorists, based on an admission to investigators that he trained in weapons and explosives at an al Qaeda camp in Pakistan last year. Zazi appeared in Denver federal court yesterday on the only charge he is currently facing--lying to federal investigators (via The Associated Press ). Zazi was ordered to remain behind bars but is slated for an extensive hearing Thursday on his detention. Meanwhile, his father, Mohammed Zazi, facing an identical charge of lying, is allowed to post $50,000 in bail and serve home detention. In New York, Ahmad Wais Afzali, a prayer leader at a Queens mosque, also appeared in federal court yesterday for lying to investigators about telling the Zazis about the investigation. As the probe unfolds, Wendy Aiello, owner of Aiello Public Relations and Marketing in Denver, has been inundated with phone calls and e-mails, some "threatening," for aiding Najibullah Zazi's attorney, Arthur Folsom, writes the Denver Business Journal . Here's an unrelated issue she might be asked about: Folsom is facing a marijuana possession charge but claims the weed wasn't his (via The Associated Press ).