Police found 30 dead dogs and cats inside the home of a CEO of an animal sanctuary following complaints about the "smell of death".
Caroline Dawn Pennington, 47, was arrested on Friday following the grisly discovery of 28 dog corpses and two decomposing cats in cages.
Pennington is the CEO and director of GROWL, an animal rescue non-profit based in South Carolina, US.
She has now been charged with 30 counts of ill-treatment of animals.
Richland County Sheriff Leon Lott described the horror scene as one of the worst animal cruelty cases he had ever seen.
He said in a statement: "It’s appalling and it’s heartbreaking. This is someone who was entrusted by the community to care for these animals and find them homes. She betrayed that trust and she betrayed the trust of these innocent animals who relied on her."
Richland County Sheriff’s Department said the animals likely died from starvation and dehydration.
They were found lying in their own waste and, based on the amount of decomposition, investigators reckon that they had been neglected in their cages for up to nine months.
Authorities said Pennington was a well-known figure in South Carolina's animal rescue community.
As well as running GROWL, she was also employed by the Kershaw County Humane Society. That is no longer the case.
Kershaw County Humane Society said in a statement: "We were unaware of the former employee’s actions and are truly shocked and heartbroken.
"Our dedicated staff will continue with our mission to serve the lost and homeless pets of Kershaw County."
Pennington is also under investigation for possible fraud given that GROWL is registered as a non-profit organization.
Anyone who has donated to GROWL in the past year has been urged to contact the Richland County Sheriff’s Department.