Don’t direct the anger and frustration you are likely to feel about the assault at the survivor. They will already be worried that what has happened to them will hurt those close to them.
Reassure them that you know it isn’t their fault, and if you do feel anger, make it very clear that it is directed towards those who committed the assault and not them. Remember that threatening to take the law into your own hands is not helpful; it can make them feel even more unsafe, make them distressed to see you so upset, or could worry them that you’ll get into trouble or get hurt. It can also make them feel out of control of the situation and that their needs are again being ignored.
You may need to ask friends or other trusted people for support and ideas about how to deal with your own understandable feelings of anger and frustration.