COPENHAGEN, Denmark — Danish police said Tuesday they were closing their investigation into the devastating fire that destroyed more than half of Copenhagen’s Old Stock Exchange, saying there was no indication that the blaze was the result of a criminal act.

Despite extensive forensic investigations, a review of surveillance and the interview of a large number of witnesses, “it is not possible to determine the cause of the fire in the historic stock exchange building,” said Brian Belling, the Copenhagen police officer in charge of the investigation.

“Our assessment is that we have explored all relevant investigative avenues in the case,” Belling said at a news conference, adding that no one has been charged in the case.

Belling said the video footage included hours of footage from inside the Stock Exchange that was not affected by the fire. He added that no flammable liquid was found.

In the early morning of April 16, a violent fire struck the 400-year-old building, a major tourist attraction. The fire toppled its green copper roof and iconic dragon tail spire. Two days later, a large portion of the building’s exterior wall collapsed inward.

As the fire raged, many, including ordinary people, ventured out to save works of art and about 90% of the cultural objects were saved from the building.

One hypothesis was that the fire started in connection with the renovation, Belling said.

He said the fire was believed to have started under the roof, which was encased in scaffolding due to ongoing renovation work due to be completed for its 2024 anniversary.

“There are guidelines on listed buildings when you renovate them. Our view is that they were followed to the letter,” said Tim Ole Simonsen, a senior member of the Greater Copenhagen Fire Department, in the same press conference. “Then you can discuss whether they are good enough.”

On September 24, King Frederik X of Denmark laid the “foundation stone” in part of a red brick wall that survived the mid-April fire, marking the start of a years-long reconstruction plan.

The owner of the downtown exchange, the Danish Chamber of Commerce, said it would rebuild the landmark, which is considered a leading example of the Dutch Renaissance style in Denmark. Construction began in 1615 and it was first opened in 1624.

The fire is reminiscent of the April 2019 fire at the 800-year-old Notre Dame Cathedral in Paris.