According to the 1910 and 1920 census records, he was a resident of Patton State Hospital and likely died there.
Courtcase
#126 Estate of Yturburu 4/13/1893
The court judged him insane & committed him to the state asylum for insane persons at Napa, CA on 4/13/1893. He was there for at least 9 years.
He was related to one Bertrand Garat in Los Angeles (he was not related to Martin Yturburu).
Jean Burubeltz was his guardian to receive notes from M. Barcelona & Martin Hachquet.
Money was paid out of estate to Domingo Larronde for 6 months boarding & lodging and for his care & maintenance.