collision at 4-way stop (signal lights out) - left turn

recent collision as making left turn. me; west bound, following 3 cars in protected left turn lane (turning south). On coming cars taking turn stopping (treating non-operating signal as 4-way stop). At my turn; one car was stationary (in center lane), another car approaching -then stopped making a rt turn, into the same street as my turn. 3rd lane, near meridian was empty. Making left turn, when car approaching, at speed - approximately 45 - 50 mph, hits my vehicle. The approaching vehicle made no attempt to brake, basically ran the "stop sign".

At this point my vehicle is assumed totalled. Bent frame, front door, front fender, hood, roof, interior and front axel suffered damage. The front axel appears to be broken (vehicle is late model Ford SUV 4-wheel drive, the other vehicle was late model (new?) small 4 door sedan). SUV settled to rest approx 20 from point of impact (relative weigths sedan 3000lb vs SUV 4900lb), speed of impact moved SUV 20 ft sideways).

Is there any question of who may have been at fault? As mention 2 other cars were at rest, honoring the 4 way stop. the 3rd approached the intersection without stopping nor even attempting to hit the brakes.