[maniacut]

Call the cops and follow dude at a safe distance in OP's case and in all these variant popup scenarios.

I was in a similar situation last month downtown toronto near Victoria and Dundas, there were quite a few people that saw it and it didn't look domestic exactly, they could have been unknown to each other or possibly drug related but anyway I called 911 and followed the guy until he hung out in front of a store on Yonge ST. I thought cops were gonna roll by any second and pick this douche up right away but 10 minutes later and nothing so I left. During my call to the operator he asked for my info: name, etc... and I declined, I think that had a reason to do with the perceived lack of police response.