After discovering the first ECHO near the Chelsea District, you must follow her footsteps back to her apartment. Afterwards, if you head around back, you discover that two rioters are around back. One climbing up to her apartment and the other as a standing guard. You must look around the building to find Heather (927~1318). You find her in a room if you go upstairs where a deceased body is laying on the floor with Heather Lau's guitar next to the body with the strings broken. Heather is in a corner hiding. She explains how she had to break her guitar over the man's head because he had frightened her. There are other things to collect when you enter the building.
Following completion of the side mission, Heather will appear on the western side of the Base of Operations where the refugees stay, providing musical entertainment. She will only start playing when the player enters that side of the base.