I think the Sheriff's office social media post should clear up a lot of confusion regarding what they can and cant do. Sure, they can ask her to come in. But Miranda permits her the option of agreeing to or not. Miranda permits her the option of speaking or not.
They need evidence to charge her, so they need Tiger's body or the original of the photo. Or the original device that took the photo.
That original has likely been long deleted unless her parents (mom allegedly took the photo, right?) do the right thing and turn over the device.
I hope this family and this adult woman choose to do the right thing, but the Sheriff's office is shoveling sand against the tide right now. It isnt their fault. They have to follow the law. There is no deference being shown to her. It is quite likely that they are pushing harder because of the out cry.
I do hope the vet clinic is reviewing any records of any animals she has assisted since she was hired by them. I think they are.