The New York Times Retracts the Sicknick Story, page-9

There is still some question about the fire extinguisher, and I'm okay if jambo12 has the correct details from official sources.

There is video of a fire extinguisher being thrown at police, with at least one officer being hit in the head.

There is a chance it wasn't Sicknick who was hit, but let's see what jambo12 comes up with.