A B.C. Supreme Court judge will decide if a schizophrenic man who killed his father and injured his mother while taking multivitamins instead of his anti-psychotic medication is criminally responsible for the attack.

Jordan Ramsay, 27, is charged with the second-degree murder of his father, Donald Ramsay, 53, and the attempted murder of his mother, Wendy Ramsay.

The accused man has admitted to the November 2011 killing, but has pleaded not guilty. Both his lawyer and the Crown prosecutor say Ramsay should not be held criminally responsible due to his mental disorder.

By the time police arrived at the family's North Vancouver townhouse, Ramsay's father was dead, and his mother was seriously injured after their son bludgeoned them in their bed with a wrench, according to an agreed statement of facts submitted to the court.

Multivitamin treatment questioned

During the trial underway this week in Vancouver, the court heard evidence that at the time of the slaying, the accused was off his prescribed medication and was trying to treat himself with a brand of multivitamins called True Hope Empower Plus, which is marketed on the internet to people with mental illness.

Leeann Ramsay, aunt of the accused and sister of the deceased, says families must see that their mentally ill loved ones stay on prescriptions. (CBC)

Leeann Ramsay, the aunt of the accused, believes the family's attempt to control his illness with an alternative therapy rather than his psychiatrist's prescription had a role in his state of mind at the time of the killing.

"Jordan went into a psychotic state earlier in the day and was having delusions," Leeann Ramsay told CBC News on Tuesday.

"He thought that Don was an alien and had to go in and make sure he was dead."

The court heard that Ramsey has a long history of going off his anti-psychotic medicine and ending up in crisis.

The evidence shows that at the time of the murder he was off his prescription, and the only pills found at the crime scene were vitamin capsules.

The court heard months earlier a psychiatrist warned "Mr. Ramsay was trying to treat himself with Truehope multivitamins," and his parents were warned he was at risk of relapse if his dose were lowered.

But just two days before the murder, a North Vancouver nurse reported, "His mother stated she wanted him on Empower Plus vitamins, and she believed she had permission to reduce his medication."

Leeann Ramsay told CBC News that Jordan's grandmother had serious concerns about the alternative treatment as well.

"My mom had various conversations with them about Jordan weaning off his anti-psychotics and trying this alternative megavitamin therapy, and my mom was very much against it.

"She begged the mother not to decrease or stop the medication, and they were convinced this was going to be a cure."

Company defends vitamin treatment

The supplements are made by Truehope, which has had several clashes with Health Canada. But the company's operator says while it does not promise a cure, the vitamins can be effective in some cases.

"A number of people have used this protocol for schizophrenia and have been extremely successful," Truehope president Anthony Stephan told CBC News.

But Leeann Ramsay believes her brother would still be alive if his son had stuck with his prescribed medicine.

"If Jordan was properly medicated under a psychiatrists care, he'd be here today," she said.

Ramsay said her brother was a good father to Jordan.

"I want to warn people, I think it is just needless what happened and [Donald] was the kindest, most gentle person and his demise was not right."

Ramsay says people should be warned not to allow family members to go off medicine prescribed by a psychiatrist.

"This is a really serious disease and you have to be properly medicated and you can't mess around with alternative medicine," Ramsay said.

She also said she wants someone to investigate whether the vitamins played any role in her brother's death.

Jordan Ramsay's psychiatrist, Dr. Leanne Meldrum, testified Ramsay is fragile, in deteriorating mental health and will need long-term care in Coquitlam's Forensic Psychiatric Institute, where he currently is a patient, before he would ever be considered safe in the community.

His mother has been discharged from hospital but is still recovering from her extensive injuries.

With files from the CBC's Natalie Clancy