Matthew de Grood has already been found fit to stand trial, but the Crown had asked for a mental assessment to determine if he could be found criminally responsible if convicted.
The Crown and defence asked a judge Friday to put a publication ban on the information in the assessment, arguing it could be prejudicial at trial.
Judge Joanne Durant said she didn't believe she had the jurisdiction to grant a full publication ban in the case, but did grant an interim ban until Oct. 7 to allow media time to argue against the move.
"His right to a fair trial dictates that a publication ban would be in place," Crown prosecutor Neil Wiberg said outside court.
"If witness statements are released it may or may not be evidence before the court. But if that's released the concern is it could affect the selection of the jury and affect the accused's right to a fair trial."
De Grood, 23, was charged in April with first-degree murder in the stabbings, which happened at a party near the University of Calgary to mark the end of the school year.
Zackariah Rathwell, 21; Lawrence Hong, 27; Joshua Hunter, 23; Jordan Segura, 22; and Kaiti Perras, 23, were killed.
Police have not said what they think motivated the attack, but say de Grood was invited to the party April 15 and mingled with guests before violence broke out.
Clad in a blue inmate jumpsuit, de Grood appeared via closed-circuit television in court Friday.
The man's father, Douglas de Grood, who is a Calgary police inspector, and his mother Susan sat in the front row during the proceedings. It was the first time they attended one of their son's court appearances.
"It is difficult for them," said defence lawyer Allan Fay.
"Obviously they're very aware the scrutiny is on them, but they feel it's important for them to continue to show not only do they support their son, but their sympathy and compassion for the victims in this matter."
One half of the courtroom was filled with friends and family of the five victims. They held hands and hugged each other during breaks in the proceedings.
"They're obviously extremely distraught. They were five outstanding young people who were murdered in this case," said Wiberg.
"Obviously they're very upset. We've had meetings with the family face-to-face explaining the process. The police also contact them on other occasions so they know what the court appearances are about."
A preliminary hearing to determine if the charges proceed to trial is to start March 2. The hearing will go ahead unless the defence decides to waive its right to it.
De Grood has been in psychiatric care since his arrest and is taking medication, said Fay.
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