On his way back, he was murdered in Trieste on 8 June 1768, in a hotel bed by a fellow traveller, a man named Francesco Arcangeli, for medals that Maria Theresa had given him.
På tilbagerejsen blev han myrdet i Trieste den 8. juni 1768 i sin hotelseng af Francesco Arcangeli, der ville stjæle nogle medaljer, som Maria Theresa havde givet ham.