The fire at the Bellevue Mill in Hillsborough last week has been deemed “suspicious but undetermined,” the town announced Thursday evening.

A release says a large amount of debris remains at the burned section of the mill.

Hillsborough fire marshal Jerry Wagner said in a release, “We know about where the fire started and what was there and what wasn’t.” Wagner added police are investigating leads as to who may have caused the fire from information obtained during the investigation.

Wagner said that the owner of the building is concerned about theft from the property.

“They realize people are curious, but curiosity doesn’t give anybody permission to trespass or take anything,” he said. “This is private property, and any theft or trespassing will be prosecuted.”

The site is still unsafe due to a large amount of debris that remains.

Officials say the investigation will continue but the property has been turned back over the owner.

Anyone with additional information is asked to contact the fire marshal’s office at (919) 241-4801 or the police department at (919) 732-9381.

The Bellevue Mill is listed on the National Register of Historic Places and has been designated by the Hillsborough Board of Commissioners as a local historic landmark. Its destroyed weave room was built as an addition in 1920. The complex is slated to be transformed into apartments.