Due to the bombing on the first day of Croatia's Operation Storm, August 4, 1995, residents from a nursing home and patients from a psychiatric ward were evacuated from the village of Petrinja to Dvor.
By 8 August, a Krajina Serb counter attack led the Croatians to retreat outside the town, though it is unclear who controlled the area around the school.
[2] On 8 August, a group of unidentified assailants entered the village and took the patients to the main hall of the school and executed them.
[2] A Danish U.N. peacekeeping force under the command of Jorgen Kold who had been stationed in Dvor watched the massacre unfold through the large shattered windows of the school.
[3] According to Kold, his unit observed at least three Croatian soldiers with baseball caps and backpacks, near the camp on the morning of the massacre and "either they're covering it up, or someone doesn't want to remember".