Chelsea police are continuing to investigate two separate Monday morning shootings that resulted in one injury, four arrests, and the recovery of three firearms. Police responded to the first shooting around 8:40 a.m. on Fifth Street. A juvenile was shot in the leg and transported to Massachusetts General Hospital with non-life threatening injuries, according to police. Another juvenile was identified in connection with the shooting and arrested. Shortly after the first shooting police were dispatched to the area of 63 Washington Ave. for a report of gunshots.