There have been several arrests already. Thus far it seems to be right wing extremists.
For example, the lady who was shot trying to enter the VP bunker has a social media profile with extensive Qanon related postings.
Another was a Republican member of the House of Representatives. He was caught because he livestreamed himself breaking the law, as all genius criminals do.
The story about Antifa being in the riots was made up out of whole cloth by the Washington Times. The company they cited put out a press release saying that they had done no such thing and the whole story was a fabrication.
There were definitely some folks there with mayhem in mind.