NEWTOWN, Conn. — When the old Sandy Hook Elementary School is demolished, building materials will be pulverized on site and metal will be taken away and melted down in an effort to eliminate nearly every trace of the building where a gunman killed 26 people last December.

Contractors also will be required to sign confidentiality agreements and workers will guard the property’s perimeter to prevent onlookers from taking photographs or videos.

The goal is to prevent exploitation of any remnants of the building, Newtown First Selectman E. Patricia Llodra said Tuesday.

“We want to be absolutely certain to do everything we can to protect the privacy of the families and the Sandy Hook community,” she said. “We’re going to every possible length to eliminate any possibility that any artifacts from the building would be taken from the campus and … end up on eBay.”

Demolition is set to begin next week and be finished before the Dec. 14 anniversary of the shootings. Town voters last month accepted a state grant of $49.3 million to raze the building and build a new school, which is expected to open by December 2016.

The contractors’ confidentiality agreements, which were first reported Monday by The News-Times of Danbury, forbid public discussion of the site as well as photographs or disclosure of any information about the building.

Llodra, the superintendent of schools and other town officials have been discussing how to handle the demolition for weeks. Llodra said they want to shield the victims’ families and the community from more trauma, and don’t want any part of the school used for personal gain.

Most of the building will be completely crushed and hauled away to an undisclosed location. Some of the demolition dust may be used in the foundation and driveway of the new school, Llodra said. The town also is requiring documentation that metal and other materials that can’t be crushed and are hauled off-site are destroyed, she said.

In addition to the demolition crew confidentiality agreements, the project management company, Consigli Construction, also may do background checks on the workers.

“It’s a very sensitive topic,” Selectman Will Rodgers told The News-Times. “We want it to be handled in a respectful way.”

Adam Lanza, 20, killed 20 first-grade children and six women inside the school before committing suicide. Authorities have not disclosed a possible motive for the massacre.

Sandy Hook students have been attending classes at a former school in neighboring Monroe that was renovated specially for them.