A 17-year-old boy has been charged with sexually assaulting a 15-year old girl on Chicago's North Side in November. The assault occurred in the 2900-block of West Wilson Avenue in Ravenswood Manor. The suspect was arrested Tuesday in the 6000-viewer. Police were searching for two other suspects, one of whom allegedly held a second girl at knifepoint. The incident was reported to have occurred near the homes of several teenagers.