FORT PIERCE, Fla. A criminal investigation is underway at the Humane Society of St. Lucie County's Fort Pierce location.

A team of at least a dozen detectives served a search warrant late Wednesday morning and into the afternoon, giving them full access to the property.

Detectives could be seen in areas where animals are housed or cared for, and nearly every one of the multiple buildings on property. After a few hours, detectives were seen carrying out boxes of documents and computers.

Detectives say the search warrant was approved as part of a felony criminal investigation, though it is too soon for detectives to say which specific crime or potential criminal charge they are pursuing through the investigation.

WPTV confirmed the investigation was prompted by a complaint from volunteer Dale Mutchler, who made headlines as the volunteer who found the body of Christine Liquori in May. Liquori was the volunteer mauled to death by a pit bull mix at the shelter.

Mutchler gave a laundry list of concerns to law enforcement after he said management did not act on concerns he brought to their attention.

“The board, the management, the medical team, they need to go. All of them. They need to go,” Mutchler said.

The complaints ranged from operational, structural and safety concerns to animal neglect allegations.

In his complaint, he details concerns about animals not being given adequate care, such as a dog passing out which he was able to 'bring back' by hosing it down with cold water. When he notified veterinary staff, he says the staff did not examine the dog for five days.

The alleged neglect, he says, has also turned deadly for some animals, including puppies recently seized by law enforcement from an animal neglect case and placed at the Humane Society of St. Lucie County for temporary care.

“There were quite a few animals that died due to the lack of care. Due to neglect. Absolute neglect," Mutchler said.

Some puppies, he said, were killed by rats.

“The rats were so bad in other areas that I had to wind up setting multiple traps just around the cages where the babies were to save them and keep them alive. No one else bothered to keep them out of the rats reach.”

Law enforcement not confirming if these allegations are part of their investigation or have risen to the level of potential criminal activity.

Detectives say they still have 'many' more interviews to conduct Wednesday.

Business operations are unaffected by the investigation. The public can still donate supplies to care for the animals and adopt animals in the custody of the Humane Society of St. Lucie County.