WASHINGTON — FBI agents planned to interview the crew of a U.S. cargo ship Saturday as the bureau began building a criminal case against Somali pirates who attacked the ship and took the captain hostage. The Maersk Alabama arrived safely in Yemen on Saturday, three days after Somali pirates stormed the ship, failed to hijack it, and fled in a lifeboat with the captain. "The FBI has informed us that this ship is a crime scene," John Rhinehart, president of Maersk Shipping Line said Saturday, explaining why crew members cannot immediately leave the ship.