Several witnesses came from Ottawa to testify including Jenni Byrne, who has served the prime minister in senior roles in his office and in the Conservative party.
Magnotta, accused of first-degree murder in the slaying and dismemberment of Chinese engineering student Jun Lin, has pleaded not guilty to five charges and opted for a jury trial.
Magnotta is facing four counts in addition to the murder charge: 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.
Byrne, who is now the director of political operations for the federal Conservative party, testified in a Montreal courtroom as the hearing entered its ninth day. She delivered her account matter-of-factly, with no display of emotion.
Magnotta, meanwhile, sat impassively and listened. He was shackled and seated in his fortified prisoner's box in the high-security courtroom.
Evidence presented at the preliminary hearing is subject to a publication ban. The hearing is to determine whether there is enough evidence to send Magnotta to trial.
The evidence heard is kept under wraps until the criminal case comes to a conclusion. While the preliminary hearing is taking place in Quebec court, any eventual trial would be heard in Quebec Superior Court.
Byrne's brief appearance came as a group of Ottawa-based witnesses testified. They included two Ottawa police officers and a Canada Post inspector.
Witnesses were heard through mid-day Thursday, when the hearing adjourned until April 8. Witnesses from Europe, Vancouver and Montreal are scheduled to be heard after the pause.
Police witnesses have made up the bulk of the roughly two dozen people to testify so far.
The court has also heard from a journalist from the United Kingdom, two Montreal apartment building employees, a number of Canada Post employees and a trio of medical experts.
Magnotta collapsed in court this week after watching video evidence. He has appeared to be wiping away tears at times and has often held his hand to his mouth during testimony.
Both the Crown and the defence told Judge Lori-Renee Weitzman that one more week in April should be enough time to complete the hearing.
The hearings have produced some bizarre twists.
The defence tried to have the public and media barred altogether from the proceedings, but the judge rejected the request.
Then a member of Magnotta's legal team withdrew from the case after the Crown raised the possibility of a conflict of interest.
The family of the victim has travelled to Montreal for the hearings but has attended them only sporadically.
A family lawyer said Jun Lin's father, mother and sister have come from China, at considerable cost, in order to honour their relative's memory and follow the proceedings.
Lin's father, Darin Lin, left in tears one morning while graphic evidence was being presented.
Jun Lin, 33, was his only son.
Lawyers for the Lin family, working pro bono, have attended on their behalf.
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