The noises Sunday in Spanish Town sounded like bombs exploding.

The first boom might have been dismissed as a malfunctioning transformer, or an out-of-place thud, neighbors said.

But after the first bang about 11:30 p.m., two more on Monday about 5:50 a.m. and 6:10 a.m., and another about 9 a.m., residents in the tight-knit historic district next to downtown worried they were hearing gunshots, blasts from the nearby Exxon Mobil plant, or attacks on the neighboring Capitol building.

“It was shaking the bed while we were sleeping,” said Spanish Town resident Blake Hartman, 27, of the booms.

Another local, Travis Moore, 31, said he heard loud bursts while at his residence, a few blocks from where debris from suspected explosives was eventually found in the 600 block of Spanish Town Road.

The bizarre series of events lit up an online Spanish Town message board Monday and Tuesday, touching off concerns about area security. And news of an arrest in the case Monday only partially satisfied questions about the logic, if any, behind the alleged actions of a neighborhood resident.

Baton Rouge police began gathering string in the case when a complaint of a threat came in about 9 a.m. Monday, department spokesman Cpl. Don Coppola said.

Dean Hebert, 34, had tried to confront someone at an office in the 300 block of Third Street, leaving behind his business card, a police affidavit said. It came a little more than a week after the business received a sinister voicemail on Oct. 2.

“Hey Bob, It’s a great day to die,” the message said, according to the affidavit.

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Employees at the business soon found a social media profile for Hebert, who posted a video showing what appeared to be an explosive device, the document said.

By 11:22 a.m. Monday, Hebert was arrested, Coppola said. Hebert was accused of displaying a fake explosive device — due to the video — improper telephone communication and possession of marijuana after officers found drug paraphernalia in his apartment.

Officers examined charred rubble outside the apartment where Hebert was living in the 600 block of Spanish Town.

“Evidence at the scene indicated that the defendant had set off small explosions and it was verified by neighbors and witnesses,” police said in the affidavit.

However, Hebert was not booked in the “small explosions” for what police believe were actually fireworks, due to lack of evidence, Coppola said.

“In the morning we seen like some firework shells, like some mortar shells, and the cops came down here and had people doing investigation,” said Hartman, who lives in an apartment above Hebert, adjacent to the outdoor space with the blackened ground.

It remains unclear why Hebert allegedly targeted Bob Dean Enterprises Inc., a real estate outfit, in his voicemail.

A woman at that workplace acknowledged Tuesday the office received the threat but declined to comment.

Pressed about Hebert’s relationship to the company, she said, in muffled tones through a glass door, “We have no idea who he is.”

Multiple efforts to reach parents of the accused were unsuccessful Tuesday.

Hebert remained jailed Tuesday evening and was assigned a $22,500 bail with a stipulation that he must be evaluated by a doctor before being released, said East Baton Rouge Sheriff’s Office spokeswoman Casey Rayborn Hicks.

East Baton Rouge Parish District Attorney Hillar C. Moore III said the stipulation was made because of Hebert’s past psychiatric issues.

Travis Moore, the Spanish Town resident, said the entire situation brought to mind recent events of domestic terrorism across the U.S.

Besides the explosions, Moore said he’s been tracking vandalism to dumpsters and porta-pottys.

There were 10 separate calls about burning dumpsters and porta-pottys in downtown received between early Sunday and early Monday, said Baton Rouge Fire Department spokesman Curt Monte. No connection has been made between Hebert and the fires, he said.

“Everyone’s on edge right now,” Travis Moore said, adding he’s one of the few people raising children in the neighborhood.

“Our son was born here in Spanish Town. We’re trying to raise a family in downtown and live downtown and work downtown, so we really believe in downtown,” he said of the general area, in contrast to suburban zones.

But the recent days’ events made him think about how someone could be making Molotov cocktails or firebombs in his neighborhood.

“Unsettling would be the word,” he said.

Follow Maya Lau on Twitter, @mayalau.