The 37-year-old Canadian citizen was last seen by hospital staff at 9 a.m. PT on Tuesday morning, wearing a dark grey plaid shirt and blue jeans.
He is described as Hispanic, is six feet two inches tall and weighs 180 pounds. According to police, he suffers from a mental disorder and should not be approached.
Desperatus-Amator-DeTanza made headlines in 2004 when, according to newspaper Diario ABC Color, he was living in a hotel in Paraguay.
According to the Spanish-language newspaper, he went to the Canadian consulate, got into an argument with an official and shot him in the shoulder.
The victim, Alvin Fehr, survived and Desperatus-Amator-DeTanza was sentenced to jail in Paraguay.
The Paraguayan court recognized he had a mental illness, but it is unclear how he ended up back in B.C. at Cottonwood Lodge, which provides intensive psychosocial rehabilitation.
Anyone who sees Desperatus-Amator-DeTanza is urged not to approach him but to contact local police immediately.
Anyone with any information about his whereabouts is asked to contact Coquitlam RCMP at 604-945-1550.