BOSTON (AP) — An explosion early Saturday at Harvard Medical School appears to have been intentional, according to authorities, although fortunately, no injuries were reported. Responding to a fire alarm, a university police officer attempted to stop two unidentified individuals who fled from the Goldenson Building just before reaching where the alert had originated. The Boston Fire Department conducted an investigation and confirmed the explosion was intentional, later determining there were no additional devices found during a sweep of the area. In an effort to identify the suspects, police have released grainy photographs showing two individuals dressed in hooded sweatshirts and face coverings.}