Where can I report scripters?

Do I just send a ticket to Riot support or what? I don't have any exact proof that he's a scripter (i.e. don't have him saying he is a scripter or video footage.)

However, I just played against him and looked at his op.gg and it looks pretty obvious to me that he's either a really good smurf that happens to play Xerath with Cleanse every game, or a scripter.