The group were hoping to record evidence of ghosts in the creepy deserted building, but instead found the body of Sharon Wilson, 69, within the grounds of the Kuhn Memorial State Hospital.
The building is alleged to be one of the most haunted in Mississippi, US.
The victim was found to have head injuries and after the corpse was sent to a crime lab the Warren County Coroner confirmed her death as homicide.
The unnamed paranormal investigators reported the grisly find to the Warren County Sheriff’s department.
Sgt Jason Bailess was told by the group they “knew they weren’t supposed to be at the site, but had found a body and wanted to report it.”
Mr Bailess went to the scene and blocked off the access before calling in Vicksburg Police Department.
Police chief Walter Armstrong was searching for Ms Wilson, who was reported missing the same day when the call came in.
Akeem McCloud, 20, and Rafael McCloud 33, were taken into custody for questioning over the death, but not formally charged, after being found with the victim’s car.
The investigation into Ms Wilson’s death continues.
Ryan Buell of website Paranormal State said the unfortunate incident showed that sometimes ghost hunters run into “real-world” problems while seeking answers to the unknown.