Animal Control Shot Multiple Trapped Cats In Front Of Nursing Home Employees

My mother works at a nursing home in South Georgia. For years, they've had cats on the property that employees and residents loved and cared for. Recently, the current person in charge called animal control to take the cats away as she no longer wanted cats on the property (they did not use nursing home funds to care for the cats; employees were always the one paying for their care and food, my mom being the one who mostly paid for their food as we have two cats of our own). I assume the woman in charge just no longer wanted the cats there. She expected animal control to take the trapped cats to be rehomed even though multiple employees told her animal control would euthanize them. Today, an animal control officer came and shot the cats in the cages in front of employees before putting them in a garbage bag. Multiple employees are in shock, bordering on traumatized, my mom included as she was one of the ones who cared for the cats the most. The employees want something done about this situation, but have no clue if they have any ground to stand on.

Cats were non-hostile as they have been around humans for years and were taken care of. Officer did not feel threatened considering all the cats were in traps.

Is it legal for the officer to just outright shoot an animal in front of third parties who had no idea that was going to happen and were expecting the officer to take them away? Not to mention, this took place at a nursing home with residents of poor mental states.