Amnesty International has called on its members around the world to send letters to the Thai authorities to voice concerns over the alleged torture of suspects in the Bangkok court bombing case.    The London-based organization called for the letters to be sent to the Thai Army Chief and the Thai Police Chief.    The International Secretariat of Amnesty International, based in London, issued the call on 20 March. It says two suspects, Surapon Eamsuwan and Wasu Eamla-au, were in danger of ill treatment and torture.