Two people being transported in a sheriff’s office van in South Carolina died Tuesday when the vehicle was overcome by floodwaters, the Horry County (SC) Sheriff's Office said.

The vehicle—staffed by two Horry County deputies—was transporting two female mental-health patients when the vehicle was overtaken by flooding from Hurricane Florence, according to The Sun News.

"The two deputies attempted to extricate the persons being transported," the Horry County Sheriff's Office said in a statement. "Despite persistent and ongoing efforts, floodwater rose rapidly and the deputies were unable to open the doors to reach the individuals inside the van."

The identities of the two individuals confirmed dead have not yet been released.

The South Carolina Law Enforcement Division is investigating the incident.