"Luckily unoccupied at the time - but still deeply disturbing that one of our farmhouses was torched by vandals," the 9th Earl Spencer wrote in an Instagram Stories post regarding the Tuesday, May 27 fire
A building on Princess Diana's childhood estate and final resting place, Althorp House, has been set on fire in a suspected arson attack, the family has confirmed.
On Wednesday, May 28, Charles Spencer, the late Princess of Wales' younger brother, thanked firefighters while announcing the incident, which occurred the night prior, in an Instagram Stories post.
"Luckily unoccupied at the time - but still deeply disturbing that one of our farmhouses was torched by vandals last night," Spencer wrote alongside a photo.
"Sincere thanks to @northantsfire for trying to save it," he added.
Northamptonshire Fire and Rescue Service clarified in an email to PEOPLE, "The fire was at land on the Althorp estate in Mill Lane, Kingsthorpe, Northampton, rather than at Althorp House."
In an X post, Spencer added that he was "stunned" to learn about the blaze, adding, "So very sad that anyone would think this is a fun thing to do."
Conservation manager at Althorp Estates, Adey Greeno, added in an X post on Wednesday, "The farmhouse that we lost to a deliberate act of vandalism last night has now had to be razed to the ground for safety reasons. So sad. The world we live in."
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Princess Diana was buried on the grounds of her childhood home following her death on Aug. 31, 1997 in a car crash in Paris.
The late royal was laid to rest on a small, secluded, tree-covered island at Althorp Estate known as Oval Lake Grave. While Princess Diana's gravesite is not accessible to the public, visitors can pay tribute to the late royal at a memorial erected on the property.
Per Tatler, Althorp House has belonged to the Spencer family since 1508.
Northamptonshire Police and Althorp House didn't immediately respond when contacted by PEOPLE for additional information regarding the fire.