Horry County Sheriff's Department spokeswoman Brooke Holden said a sheriff's office van was carrying two "detainees" and two deputies to Darlington on Tuesday night when it was overtaken by floodwaters.
The women were in the back of the van, in shackles.
Thompson said the deputies tried to get Newton and Green out of the van. High-water rescue teams plucked the deputies from the top of the van.
County Sheriff Phillip Thompson said in a statement obtained by ABC News that South Carolina State Law Enforcement Division is investigating the tragic incident.
"We want answers", Green's sister, Donnela Green-Johnson, said in a Facebook post. The incident is under investigation by the State Law Enforcement Division.
They had to suspend recovery efforts due to rising water.
The van was attempting to cross a flooded area of Highway 76 in Marion County when it got swept away, according to cops.
Thompson said his office was responding to court orders to transport the women from a hospital and a mental-health center. (AP Photo/Gerald Herbert) Rising flood waters in the Pee Dee area in Marion County, S.C., seen on September 17, 2018. Richardson, who serves as coroner in adjacent Marion County, confirmed their deaths that night, but authorities had to leave the bodies and van in the water until conditions were less hazardous.
"Tonight's incident is a tragedy. It makes it seem like someone took a very unnecessary risk in creating the problem in the first place".
Or northbound motorists from Georgia could get off I-95 and take either I-26 or I-20 to Columbia and then catch I-77 to Charlotte, the agency said.
Harrowing police scanner audio provides details of the efforts to save the women, who could be heard talking as rescuers scrambled to save them.
Just hours before closing the road, officials with the S.C. Department of Public Safety (SCDPS) had announced the reopening of the vital east coast thoroughfare - which experienced severe flooding in low-lying areas between mile markers 181 and 190 in Dillon County, S.C. earlier this week.
Hershberger said that her mother was diagnosed with schizophrenia three years ago and took medication for the condition; a new therapist who Green visited on September 18, determined she needed to be committed to a mental institution. At almost 7 p.m. Wednesday, State Law Enforcement Division spokesman Thom Berry confirmed the bodies had been recovered. The two deaths will push Florence's toll across three states to almost 40 victims.