I understand shutter speed often gives a false impression of RRPM on film but the RRPM does looks slow with quite a sizeable coning angle. This port engine appears to be smoking so to me it looks like an engine failure with overpitching. Also the right yaw as pitch is pulled prior to impact would indicate low RRPM as the tail rotor would have lost effectiveness.
The A109A and C are not particularly good on one engine when you're expecting the failure, when you're not they can be very unforgiving.
What I find disgusting however, are the sick comments on LiveLeak below the video frame. I truly hope the families of the deceased don't visit the site.
RIP
JJ