An explosive device detonated in front of a house in Potomac Wednesday night, blowing out windows but not causing any injuries, Montgomery County officials said.

At 9:15 p.m., residents called 911 saying they heard an explosion and smelled a strange odor, according to fire officials.

This neckace was found near the scene of an explosion in Potomac, Md. (Montgomery Fire & Rescue/Montgomery Fire & Rescue)

“We’re still analyzing the parts and components,” said Assistant Fire Chief Scott Graham.

Authorities also released a photograph of a necklace they said “may be related to the crime.” The metallic necklace appears to spell the name “Jennifer” in Hebrew.

Montgomery County fire and police investigators are working with the FBI on the case.

They ask anyone with information about the case to call the fire department at 240-777-2263. Callers can remain anonymous.