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The Boston Globe

Metro

Investigators tell of trailing suspects in series of arsons

Mark Sargent,45, (right) and Jean Marie Louis, 23, (center) have been charged with setting a West Bridgewater fire.

George Rizer for the Boston Globe

Mark Sargent,45, (right) and Jean Marie Louis, 23, (center) have been charged with setting a West Bridgewater fire.

BROCKTON — It was becom­ing almost routine for ­arson investigators: jumping out of bed several times a week to respond to yet another suspicious fire at an abandoned or unoccupied building on the South Shore.

“After the first week of ­November, there was a marked increase of arson fires,” Sergeant Michael Peters of the State Police said Wednesday after­noon. “They were occurring approximately every three nights and becoming almost nightly.”

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Peters testified at a dangerousness hearing for Mark ­Sargent and codefendant Jean Marie Louis, both of Middleborough.

The defendants were arrested Jan. 30, minutes after an ­arson at 457 South Main St. in West Bridgewater. They were charged with setting fire to a building under construction, but authorities say Sargent may be responsible for at least 23 other arson cases since September. Louis is also being investigated in additional fires.

Sargent, 45, lives with ­Louis’s mother, and the couple have a younger child.

Peters and State Trooper ­Eric Desrochers testified in Brockton District Court in a hearing to determine whether the defendants will be granted bail to await trial. Peters is expect­ed to return to the witness stand Thursday.

Attorneys for the defendants argued before the start of the hearing that allowing cameras inside the courtroom could lead to a flood of mistaken witness accounts. But the judge allowed the cameras to remain.

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When Desrochers referred to the series of arsons, both ­defense attorneys — Jason Howard for Sargent and Jennifer Sunderland representing the 23-year-old Louis — objected, saying their clients have so far only been charged with one arson. But the judge allowed the testimony to continue.

For weeks, investigators were stymied, but knew that the perpetrator used Duraflame fire starter logs and gasoline. The arsonist would spray the top of walls with accelerant, light the logs, then place them at the base of the wall to create a delayed ignition, Peters said.

Peters responded to an ­arson Dec. 19 in Scituate, at an unoccupied single-family house. Then Peters headed to Marshfield, where another ­arson had erupted on a boat dry-docked at the marina.

While investigating the scene, officers were drawn to a Toyota Highlander parked on a cul-de-sac with a view of the marina. Sargent was sitting ­behind the wheel, Peters said.

Sargent allegedly told officers he was just driving around and stopped at the location ­because as a child he would watch fireworks there.

Peters asked Sargent if he had been in Scituate earlier in the night. Sargent denied that he was, Peters said.

But police later obtained Sargent’s cellphone records through a court order and found that calls had been made from the phone near 10 arson scenes on the South Shore, at times when the fires raged.

The records showed that on the night of the Scituate fire, at 8:45 p.m., Sargent’s phone pinged off a cellphone tower in Scituate, near the scene of the fire, Peters testified.

Authorities secured a warrant allowing them to track ­Sargent using a GPS device fixed to his car. A Raynham ­detective went to Sargent’s home in Middleborough on Dec. 22 and placed the device on his Toyota Highlander.

Sargent, a wholesale car dealer, exchanged the Highlander for a Subaru Outback in early January, and authorities placed the GPS on the Subaru.

On Jan 30, police noticed the Subaru traveling erratic near the 400 block of South Main Street in West Bridge­water. Desrochers testified that he rushed from home in his cruiser toward the blip on his laptop, and as he did so, he heard on his radio that a fire had just been called in near the area where the Subaru was tracked. Police stopped the ­vehicle, ordered both men out, and arrested them.

Louis’s shoes were covered with mud from the washed-out building site, and his pants were spattered with dirt, State Police said. A pair of gloves, reeking of gasoline, were also found in the front pocket of Louis’s black, hooded sweatshirt, prosecutors said.

Brian Ballou can be reached at bballou@globe.com. Follow him on Twitter @GlobeBallou.

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