I too am sorry to hear that this happened to you and your dogs,and very sorry to hear about your loss.
I haven't read everything other members have said, but I did quickly skim over and agree with one thing in particular...you must get the dog properly assessed by a qualified behavioral trainer and you must see a vet to have any necessary health checks carried out, prior to making any decisions. I understand the pain and shock you must be in, but agree that these things rarely do not happen out of the blue or without reason. Incidents like this often can have contributing factors such as medical or on going behavioral problems that have not been diagnosed or picked up on. If your dogs are similar in age, breed and the same sex, then this most certainly would have played a role in what happened given that they would be reaching maturity around 3 years and I do believe, if Bailey was the perpetrator she would have some sort of injuries or blood on her too. I understand your pain, but please do not send her away without looking into why this happened first.
In regards to your vets opinion that "this kind of damage from dogs who are trained to kill", I tend to disagree. Any dog has the ability to severely injure another dog, however it does show that the dog who attacked your Tae had a lack of bite inhibition and needs professional help from a behavioral trainer who deals with aggression. I also would be checking signs that your dog, has not in fact been a victim of a dog attack by another dog off the property. It could be a possibility that your dog escaped and came home or that someone let your dog out and returned him, after being attacked by another dog?
If you do wish to rehome her, I would be calling an experienced breed specific rescue who will assess her prior to rehoming and be particularly careful in selecting a new house for her, if she can in fact be rehabilitated.