Mr. Maia just stated that the causes were various and sequenced.
The xponder in question ... is the one that goes to standby mode after a few seconds, when a code is not set immediately? I've heard that from a pilot who flies an aircraft with one of those.
Obviously, the authorities have to find the people responsible for the accident, but the Federal Police or the Air Force are the least qualified, in my opinion, to make any findings in any air accident.
They need an independent entity, like the NTSB or the CTSB, composed of qualified accident investigators, to lead that type of analysis.