Reinis Pupolins, 22, attacked Ashwin Desai at the Hampton by Hilton hotel near Luton Airport in September 2015.
Psychiatrists said Pupolins - who pleaded guilty to manslaughter on grounds of diminished responsibility - suffered "genuine psychotic symptoms".
Mr Desai, from Ontario, Canada, died three months after he was attacked.
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Pupolins had told staff at another hotel he was being spied on by Russian mafia over credit card fraud. He had not been sleeping, Luton Crown Court heard.
Father-of-one Mr Desai, an IT engineer who was married to a university professor, was retuning from the gym in the Hilton, where he was staying for business, when he encountered Pupolins.
Judge Michael Kay QC said he was "viciously and repeatedly attacked and very seriously injured".
He added: "He was flown back to Canada on 31 December, where he died. It is unimaginable what his family has been through."
The judge made an order under the Mental Health Act which means Pupolins will be detained indefinitely in a secure psychiatric unit.
A Latvian man who battered a hotel guest with a fire extinguisher after "voices told him to kill someone" is to be detained in a mental health unit.