brussels belgian federal prosecutors say tuesday charge two people foil attack 2015 high-speed train brussels paris august 2015 machinegun-toting attacker wound three people thalys train overpower passengers one series militant attack rock belgium france past two years two men name mohamed b. youssef s. indict participation activities terrorist group prosecutors say among four people detain police monday house search brussels elsewhere belgium two others release interrogation belgian prosecutors charge two foil attack high-speed train