A 22-YEAR-OLD woman, Ms Chan Wing-man, plunged 13 floors to her death from a flat in City One, Sha Tin, last night. Two death notes were found in the flat - one addressed to her mother and the other to her former boyfriend, the occupant of the flat. Initial police investigations indicated Ms Chan entered the unattended premises with a duplicate key. Police said no foul play was suspected. The incident happened at about 9 pm.