For weeks, some residents in Berkeley, California, have had a hard time staying asleep thanks to loud booms in the middle of the night.
"I’d say it was around one in the morning, scared the hell out of me," Rachael Marzoline told KPIX-TV of what she heard. "I jumped out of bed."
Marzoline told the news station that this boom occurred Sunday night, but Joel Bryant said he has heard them at least eight times within the last month.
"We’re puzzled by it,” he told KPIX. “It’s not as crisp as a gunshot. It sounds like an aerial bomb explosion."
Some on Twitter have associated the #berkeleyboom with a flash of light, and an occurrence happened as recently as early Wednesday morning.
Here are some tweets from previous incidents.
Heard the #berkeleyboom. I knew I could count on you for corroboration, Twitterverse.— Krista Meyer (@missingbravo) March 4, 2015
Berkeley police told KGO-TV that it's most likely fireworks, though they have yet to find proof.
"People are reporting like a large flash of light and then also maybe some smoke in the area which could be just left over from the actual device going off," Officer Jennifer Coats told the news station.
Watch KGO's report on the mysterious booms:
Front page image via Shutterstock.