We can't even get into the blade creep and micro fractures at the neck that would be present from blade failure. To be sure, there are signatures, but many would not be present to the naked eye. For comparison, Google a few ATSB or NTSB full accident reports. You'll see the kind of testing that goes along with a PT6 blade failure. I think the inference is that the engine turbine must have failed due to the intact compressor, but then there's nothing in front of the compressor anyway.
Are there any pictures of the centrifugal compressor? Burner assembly?