A series of mysterious explosions that shattered the nighttime calm along West MacArthur Street over the last two weeks, was resolved with the discovery last week of a 4-inch PVC pipe embedded in a five gallon bucket of concrete.

The homemade device had apparently been used as a rocket launcher for illegal explosives fired into the nighttime sky.

Found near a dirt lot at Hayes Street and West MacArthur, police surmise the culprits snuck into the lot under cover of darkness, ignited the ordinance and were gone before anyone could catch them.

According to Sgt. Spencer Crum, with the Sonoma Police Department, it is a felony to fire an explosive from such a launcher as it thus becomes a dangerous weapon.

The mortar launcher was found by a neighborhood resident. Police are seeking information about anyone responsible for its use.