Online abuse at my DD what can I do?

[Tinkerbellone]

Hi
My 17yo DD has aspergers. She has severe social anxiety. However, she has some online friends she has had for years. She attends a special school for anxiety but is taught one to one on her own due to her anxiety. Face to face socially she has no friends.

Last night she was sobbing and devastated (she is normally very self contained) two friends from school who she hasn't heard from for over a year. Messaged her abusive chats over Snapchat. A boy who previously bullied her joined in. These girls used to be her friends when she was in year 7&8 she has loosely kept in touch via whatapp.

What do I do? She was beside herself. She refuses to tell me what they snap chatted. She cried and cried saying, 'I don't know why it happened. What provoked them. I didn't say anything.'
She doesn't lie.

There is no evidence of what they sent. But she is very shaken and upset. My heart aches for her.

What would you do? What can I do?
My friend says I should call police.

How awful your poor Dd. I would
A. Block the bullies' accounts and report their behaviour to Snapchat.
B. Make sure your Dd knows how to screenshot and to do that with any further nasty messages and send the screenshots to you.
C. Make sure your Dd knows that the bullies poor behaviour is their issue and no reflection on her as a person. She deserves decent friends and those old acquaintances just don't cut the mustard.

Take screenshots for evidence. You can report the abusive posts to the social media company. You need to see what it says to determine if it is a police matter. You can also block then from contacting your daughter again. I am sorry she is going through this.

Thank you @AnneTwacky

We had a long talk with long hugs. She doesn't particularly like hugging but lay with me for over an hour so I know how distressed she was.

I know who the names of these people and I'm so angry!

@Blondephantom thank you. She's blocked them now. But the snapchats disappear so there is no evidence and she was too distressed to screenshot anything.
My friend said go to police but with 3 first names and no evidence. Only my DD who wouldn't tell me what was said... I feel powerless to do anything. These young people will get away with doing this to my DD :(