MANILA, Philippines (AP) — Security forces are searching for three "persons of interest" suspected to be behind last week's powerful blast that killed 14 people and injured 67 at a busy night market in the southern Philippine city of Davao, police said Monday. Police have artist sketches of the three people being sought, including a man who left a backpack containing the powerful improvised bomb before it exploded on Friday, said the national police chief, Ronald dela Rosa. According to witnesses, the man who left the backpack at the open-air market hurriedly walked away from the scene, pretending not to hear those calling his attention, said the regional police chief, Chief Superintendent Manuel R.