Louis Bouthillier says authorities are preparing to head to Germany and France in May or June to gather evidence from civilians and law-enforcement personnel.
Magnotta is accused of killing and dismembering university student Jun Lin in May 2012.
He was back in court today for a pre-trial hearing, where the Crown and defence debated whether the jury should be bilingual or English-speaking only.
Quebec Superior Court Justice Guy Cournoyer doesn't have to make a final decision on the matter until closer to the trial.
The trial is scheduled to begin Sept. 8 and Bouthillier says that start date remains the goal.
"We will obviously have to wait for the witnesses to be ready and for the European authorities to be ready to welcome us and have the witnesses ready to testify," Bouthillier told reporters Friday.
"It's not definite that we will be able to make it, but we're all obviously working very hard for it to happen. Everybody wants a September trial in this matter."
The court heard earlier that the process of gathering testimony abroad by both the Crown and defence could take four to six months.
Magnotta, 31, left Canada after the alleged murder and is believed to have travelled to France and then Germany.
The case triggered an international manhunt that ultimately led to Magnotta's arrest in Berlin in June 2012.
In addition to the murder charge against him, Magnotta is accused of committing an indignity to a body; publishing obscene material; criminally harassing Prime Minister Stephen Harper and other members of Parliament; and mailing obscene and indecent material.
Magnotta has pleaded not guilty to all charges.
Cournoyer must also decide whether to admit preliminary hearing testimony from Eric Schorer, the superintendent at Magnotta's old Montreal apartment where the killing allegedly took place.
Bouthillier requested Thursday that the testimony be allowed. He explained that Schorer, who was slated to testify at the trial, had died earlier this year.