PORT GIBSON (AP) — A historic house on a Civil War battlefield has been damaged.

A press release Thursday from Mississippi’s Department of Archives and History said thieves took four wooden support beams from a 200-year-old home on a Civil War battlefield. The damage at the Shaifer House was discovered April 1 but likely occurred earlier. The interior floor and walls were also damaged.

The site is currently closed, but the state department plans to fix the damage and reopen it as soon as possible. Jim Woodrick, the director of the historic preservation division at the Mississippi Department of Archives and History, said he doesn’t know how costly the repairs will be or how long they’ll take.

“We suppose it was to salvage some historic material for some other purpose,” Woodrick said of the crime. “Clearly it was not the work of vandals — it was something that took effort, it took planning.”

The state archives department is working with the Claiborne County sheriff’s department. The sheriff’s office did not return requests for comment.

While the crime occurred almost two weeks before the press release, Woodrick said the archives department wanted to secure the site before releasing the news.

The Shaifer House sits on the Port Gibson Battlefield. Its construction began in 1826 and was the site of the opening salvo in Gen. Ulysses S. Grant’s successful campaign to capture Vicksburg.

The house was restored in 2006.

“This is not just a house in the middle of the woods. It’s an extremely important site related to Civil War history,” Woodrick said. “It was a really terrible thing that someone has done.”