There have been multiple incidents of an unknown male breaking into homes between 12:00 and 6:00 a.m. by entering through unlocked first-floor windows. Residents are urged to lock all windows (and doors) overnight, particularly those on the first floor. Residents are also urged to call police if they see anything unusual in their neighborhood such as loitering; persons in driveways or yards who shouldn’t be; and any other suspicious behavior. This activity is occurring in large part along the Beacon St. corridor along the city limits of Cambridge.