MANILA — Three suspected members of extremist groups have surrendered to authorities in Mamasapano, Maguindanao, the National Bureau of Investigation (NBI) said on Monday, March 16. NBI Director Melvin A. Matibag presented the individuals, who are alleged members of the Karialan faction of the Bangsamoro Islamic Freedom Fighters (BIFF) and Dawlah Islamiyah (DI) operating in…