Karen Sussman, president of the International Society for the Preservation of Mustangs and Burros (ISPMB), is denying accusations that 30 mustangs died of starvation at the organization’s South Dakota facility.

Founded by Velma Johnston, also known as Wild Horse Annie, to study and preserve wild horse herds in the west, ISPMB currently manages four wild horse herds and collects data on the horses’ social structures and herd dynamics.

Sussman told TheHorse.com that on Oct. 2, former ISPMB employee Colleen Burns posted accusations on the internet that Sussman had maltreated horses at the sanctuary and that 30 animals had died allegedly of malnutrition.

Sussman said Burns had recently been fired from the organization and denied the accusations.

“I cannot tell you much, but I can tell you that the 30 horses did not die of starvation,” she said, adding that her lawyer would issue a statement.

Burns could not be reached for comment.

Meanwhile, a Dewey County, South Dakota, Sheriff’s Department representative said an investigation into the alleged deaths is underway, but no one has been charged in the case.

The spokesman declined further comment on the ongoing investigation. He referred further inquiries to Dewey County State’s Attorney Steve Aberle.

Aberle was unavailable for comment.