NEWPORT — The fires stopped, but the arsonist was never caught.

In the spring, residents and business owners grew uneasy as the sun set on this historic seaport, with its renowned collection of old wooden houses and stores. Someone was setting the buildings afire in the wee hours of the night.

During a two-month period, six suspicious fires broke out in the central part of the city. The worst one occurred on May 9, gutting the House of Scrimshaw & Gifts on Thames Street and forcing the demolition of its charred remains. It was this fire, which left a scar in Newport’s popular downtown shopping district, that spurred the police to announce that the city was being preyed upon by a serial arsonist.

Three houses were scorched before the House of Scrimshaw and two more burned just several days later after the police warned the public to be on the lookout for any suspicious behavior. The damage was relatively minor in these other cases, but the pattern was similar: After darkness fell, someone sneaked behind the rear of the wooden structures and set them on fire. The police remained mum on the method used, but perplexed at the motive.

“I can’t tell you why they stopped or why they began,” said police Lt. William Fitzgerald.

Fitzgerald said the cases remain under investigation. While the public responded with lots of helpful tips, none led investigators to a suspect, he said.

“We’ve been very fortunate no one has been hurt,” said Fitzgerald, adding, “It’s a relief the fires stopped.”

Anyone with information is encouraged to call detectives.

“It’s frustrating we haven’t caught this person yet,” he said.

It’s still under investigation.

rsalit@projo.com