I'm not sure about the rare forehead but that's a cool looking dog. Certainly fits the bill for a canis panther, could also be any number of possible crosses between various breeds, but since you're in the US and LA specifically I think canis panther seems pretty likely. If it was here in australia uncropped and undocked I'd assume it was a mongrel pig dog with apbt, greyhound and dane in it, but yeah probably a canis panther. A nice animal, on the racier side of the canis panthers I've seen which is a good thing IMO.