It remains a baffling mystery.

No one knows what caused an explosive blast of noise and a flash of light on Narragansett Bay late Monday night, Dec. 3, between Barrington and Warwick.

Residents from both towns reported hearing the noise around 11:30 pm, according to WPRI-TV. But Coast Guard, police and fire crews who investigated the reports found nothing.

Mark Etheridge of Barrington, who lives near the bay, told WPRI that he was downstairs in his basement and through some small windows saw a flash of light and heard “basically the biggest explosion I’ve ever heard in my whole life.”

Etheridge said he has heard a transformer blow, “but this thing was ten times that. My whole house shook.”

The noise and light remain a mystery, though.