New Bedford Police say it wasn't a gunshot or fireworks that caused a loud boom that seemed to come from the North End last night. The loud mystery noise was heard just before 11:30 Monday night.

This caller to WBSM says she's heard what sounds like explosions several times recently. "I heard, maybe a couple of nights before, two of them. But not that loud as last night. But I thought it was coming from the Brooklawn Park area."

Another caller says he heard the noise from the next town over. "I heard the same thing around midnight. And I'm up around the Freetown State Forest. My initial thought was somebody just blew a cannon off back there!"

With Independence Day around the corner, the prime suspect is fireworks. However, police say what was heard last night was not a noise consistent with a typical firework.

New Bedford Police Lt. Amos Melo said the City's gunshot detecting system, ShotSpotter, didn't pick up on any activity last night. The system occassionally pinpoints firework detonations.

Some callers suggested the noise is simply pranksters throwing M-80's out of their car while driving around the area.