Authorities revealed that 27-year-old Chang Wen killed three people and injured nine in downtown Taipei, after earlier reports described a masked assailant stabbing passengers at Taipei Main Station and Zhongshan station.He threw a smoke grenade before moving to the Eslite department store to stab victims on multiple floors and then took his own life, prompting President Lai Ching-te to promise strengthened security and an investigation into his motive.