GERMAN prosecutors are questioning the head of a company suspected of trying to export aluminum tubes to North Korea that could be used for making nuclear arms, the Stuttgart prosecutors' office said. The company shipped tubes listing China as the destination without a permit from Germany's Bafa Export Agency, prosecutors' spokesman Eckhard Maak said. The deal was arranged by a North Korean middleman, arousing the suspicion that the real destination was North Korea, he said. "It's a hypothesis right now that North Korea was the final destination," Maak said in an interview. Whether the purchaser was North Korean or Chinese,...