Sheltie Dog Aggression My Dog Killed My Other Dog.?

My dog killed my other dog.? - sheltie dog aggression

1 year ago I had three dogs. One was a (male Scottie), the very territorial and was about 4 years. The other was a mini-dachshund (was female) 13, and the last one was a black lab mix (female) 5. My parents came to visit and brought their Sheltie, which 14 years ago. Although they have a day on the slopes with my dog killed the Sheltie. We do not know what it was and I thought, unless Scottie is territorial. We were rescuing a group to take it and him into a house with other animals. Almost a year passed without any problems. Last Friday, my lab has killed my mini dachshund. We are devistated. I had the lab, since I was 7 mos old. They were our children, and were treated very well. My laboratory has dog parks and hiking trails, where you've never had problems with aggression. She is well educated and do not have a problem with the children. Can not love, but, as they did. What should we do?