People in Yonkers, Mount Vernon, Eastchester, Scarsdale, Tuckahoe and Bronxville heard a loud noise they say sounded like an explosion early yesterday morning.

But what the noise was remained a mystery.

Tuckahoe police said several residents called about the loud noise, but that checks with the Yonkers, Eastchester and Bronxville departments yielded no answers.

A Mount Vernon man said his clock read 12:34 a.m. when he heard the boom.

Tuckahoe resident Margaret Belles was among those who heard it.

"We don't know what it was," she said. "From my house, you know, it was definitely a loud house-shaker."

The television show Law and Order was filming a car explosion Friday on Van Cortlandt Park Avenue in Yonkers, according to entertainment industry Web sites, but how late they were at work was unclear.

There was no seismic activity in the region, according to the Lamont-Doherty Earth Observatory's Web site.

It's possible the noise was a sonic boom, but the Federal Aviation Administration could not be reached last night. The National Weather Service said there was no weather condition that would have caused such a sound.

California had a similar boom mystery two days earlier. Here's the Santa Cruz Sentinel story.

Anyone with information can call The Journal News at 914-694-5077.