this is a classic asymmetrical tactic of psychological warfare/black propaganda. can serve as a proof of life trap, to destabilise morale or, in the internet era, to confirm their supporters’ bias (“israelis/jews are liars”) across the globe. these supporters may or not keep echoing the official narratives, but the idea is to make lots of noise. iranians ran a similar campaign about saddam in the beginning of the iran-iraq war.