Robby Fabbri fell over Corey Crawford. Things like this happen constantly in hockey. Most goalies shake it off, or let their teammates take care of the situation.
Corey Crawford is much more of a hands-on kind of guy, as evidenced by him going after Fabbri:
In the resulting melee, Fabbri got dinged with an interference minor, Pietrangelo got a roughing, Shattenkirk got a spearing, Andrew Ladd was also handed a roughing minor, and Crawford was given a roughing minor against Fabbri.
So, the Blackhawks got a power play, which Duncan Keith converted on to put the Blues up 2-1. Granted, I'm not one to cry conspiracy, but I will point out shitty calls, and this was probably a shitty call.
The turn of events was so out of the ordinary that even Mark Lazerus, Blackhawks beat writer, had this to say:
THE #BLACKHAWKS GOT A POWER PLAY OUT OF THAT? That's criminal.— Mark Lazerus (@MarkLazerus) April 20, 2016
Vladimir Tarasenko would soon score his second of the evening to tie the game up at 2 heading into the third period.