A medical doctor says his brother-in-law's death in a Nova Scotia prison after being Tasered was preventable, because the man suffered from paranoid schizophrenia and should have been placed in a psychiatric hospital.

"This is a major point: he was psychotic, not a criminal," Dr. Hunter Blair, a family physician, told CTV Atlantic on Tuesday.

Howard Hyde, 45, was off his medication when he was arrested last week for assaulting his partner. He had an intense fear of stun guns, having been Tasered by officers in 2005, and had become convinced the shock had damaged his heart.

Last Wednesday, he struggled with police after his arrest and they used a Taser to subdue him. He went into medical distress and was hospitalized for up to three hours, but then placed back in police custody.

After a court appearance the same day, Hyde was taken to the Central N.S. Correctional Facility in Dartmouth. He had two confrontations with security guards, and five guards struggled to restrain him. On the following morning, 30 hours after being Tasered, he died of unknown causes.

The RCMP said it could take up to a year before officials know exactly what killed Hyde. Initial autopsy results on his organs were inconclusive, requiring further toxicology tests.

Blair said he didn't want to blame any single individual for what happened to his brother-in-law, but said the correctional facility should at least have been aware of Hyde's mental illness.

"There was a succession of errors that should be looked at so that this never happens again," he said.

Blair also emphasized that he was not a coroner, but only a doctor who has read the literature on Tasers and so-called "excited delirium," which he believes may have been the cause of Hyde's death.

"I personally believe the Tasering had little to do with it," he said.

"The conflict with the people at the correctional centre and Howard's death are directly linked. I'm not suggesting for one minute that they killed him. What I'm saying is that if someone is in a psychotic delirium state, physical restraint can lead to such an imbalance in their metabolism that they suffer acute death."

The jail guards were not formally informed that Hyde had been Tasered or that he suffered from paranoid schizophrenia.

"Someone should have had a little red flag pop up, saying, wait a minute, maybe we should not go through the formal procedure we're supposed to -- maybe we should send this guy somewhere and have him looked at," he said.

With a report by CTV Atlantic's Atlantic Elizabeth Chiu