I rather liked this and it teetered on the edge of my shortlist, but in the end (ha!) I decided in my very narrow nit-picking way that it wasn't quite there in meeting the genre of Urban Fantasy. You've set it in a city, and the mugging is a crime of a city, but the setting wasn't tied enough into the plot for me. There's no reason given for him to have to work the magic there, as opposed to in a forest or at sea, where violence could also be meted out, thus shattering the glass. It occurs to me as I'm writing this that the Illuminati may be mages of the city, which may well add a stronger urban link -- I'm not one for reading Illuminati tales so I really don't know.
There's very little I can fault with the way the story is written. The "Nameless" is perhaps otiose, and "Behind soft footsteps" really requires a "him," there -- a comma after "Behind" would just about work if you were desperate for words, but you're not, since there are several which aren't strictly required, eg "soft" itself. For me, you could have pruned some of those -- eg "with it" isn't necessary -- and then given more background, perhaps why the magic has to take place in the city streets.
So yes to me a strong story, and one which I would have at least shortlisted had it met my narrow definition of the genre.
Cathbad has just popped in ahead of me. Just to say I wasn't confused, as I understood the mugger was after anything valuable, so a mobile phone is the obvious target, However, he's right in that it would have made it a more complete story if the stolen item was introduced earlier -- eg here as it's the phone, he might have been speaking to his fellows in a dozen different cities around the world.