I don't think the details of the gun are going to be that critical after having seen and heard the video, but, I could be wrong.
Likely a glock or a berreta though, wouldn't you think?
A DA first shot, with SA follow up shots could be a factor. Once the first goes off (about 10# pull) the following (5#) shots can almost be "sympathetic."
I think the type of gun (and his training, adherence to policy etc) will be huge in this case, on both sides.