The U.S. is for a second time attempting to prosecute five prisoners held at the Navy base in Guantanamo Bay, Cuba, for planning and aiding the Sept. 11 attacks, charging them with war crimes in a special tribunal for wartime offenses known as a military commission. Here’s an update.

Q: Who will be on trial? What are the charges?

A: The main defendant is Khalid Sheikh Mohammed, a self-described terrorist mastermind who came up with the idea of using commercial aircraft to attack the U.S. and set the plan in motion. Mohammed, a Pakistani citizen who grew up in Kuwait and attended college in Greensboro, N.C., has told the U.S. military he was responsible for the Sept. 11 attacks from “A to Z,” as well as about 30 other plots, and said he personally beheaded Wall Street Journal reporter Daniel Pearl.