Prosecutors announced indictments against two men accused of plotting to bomb New York's subway system and said a global investigation has failed to link the plot to any known terrorist group. A federal grand jury returned an indictment charging Gazi Ibrahim Abu Mezer, 23, and Lafi Khalil, 22, with conspiring to explode a pipe bomb in a subway. If convicted, the men could face a maximum sentence of life in prison. U.S. Atty. Zachary W. Carter. Police raided the suspects' Brooklyn apartment July 31, finding two potential suicide-style explosive devices, officials said. The suspects were shot as they tried to reach triggers to detonate the bombs, prosecutors said.