From AMLopedia
Rachel was Liam's neighbor from the time he first moved to Sylvan Meadows until about 2003, when she moved out. She used to torment Liam all the time, and the boys thought she was really annoying. One time, Liam ran away into his house, and she started pounding on the door, resulting in a slit wrist from breaking one of the little windows at the top of the door.
Another time, Liam was sitting on the sidewalk, and she ran over his back on her bike.
There was a long period where she wasn't seen around the neighborhood, until one day Adam and Liam saw her while they were playing racquetball.