So what exactly happened then?   

Here is my guess, based on flying in that area for years. LACFD states the aircraft went down near Baldy and Glendora roads. Hard landing.  There is a helicopter LZ at Cow Canyon Saddle, in that general area. Used by fire/police all the time.  Good place to do a PR.  Big enough for a Type 2 medium, so a 407 can use it no problem. LZ around 4500', if memory serves me. Morning temperature maybe 70 degrees? That puts the DA at 6500+. Winds, if they existed, can be tricky, swirling because the LZ is on a saddle. No wind? Now you need more power at the end of the approach. If this indeed was the area the pilot tried to land at under those conditions, that a tough demand for a 407. If this wasn't the area, who knows why it crashed, other than not enough power to arrest the rate of descent. Glad the pilot wasn't seriously injured.

Note to AMC management-the aircraft you use to cover the high desert have no business conducting scene calls in mountainous terrain, especially in the summer months.