Jury selection began Tuesday morning in the trial of a man accused of murdering two patients inside the psychiatric ward of Notre Dame Hospital.

Idelson Guerrier was a patient at the hospital in 2012 when two other patients were found dead in their room, and two other patients were attacked.

The case raised many questions about security inside the hospital, and the trial promises to be long and complex.

Guerrier was staying in the psychiatric ward and it took some time for investigators to determine he was a suspect.

He is charged with murdering Gaetan Senecal, 69, and Claude Courtemanche, 77, on June 16 and 21 of 2012, respectively.

He is also accused of attacking fellow patients Eytyxia Tsidanoulis and Yolanda Bertocchi.

The Crown plans to establish that Guerrier attacked people when staff in the psychiatric ward was not paying attention.

Lawyers are choosing the jury that will decide Guerrier's fate, a task that is expected to last until Thursday.

Justice Helene Di Salvo is also asking potential jurors about the possibility they might be racially prejudiced, since Guerrier is of Haitian origin.

The trial is expected to last three months and could very much take its toll on the resources of the Notre Dame Hospital, because the prosecution plans to call 11 doctors, at least 12 nurses, and an equal amount of orderlies and other employees from the hospital.

“Many witnesses who will come in for a short period of time to explain the behaviour of the accused and the taking of the medication because the events took place at the Notre Dame Hospital,” said prosecutor Genevieve Dagenais.

The defence said it plans to call several psychiatrists to bolster its case that Guerrier suffered from mental illness.

“It will be under Article 16 of the Criminal Code,” said defence lawyer Francois Berichon.

In such cases, the defence has the burden to prove that the accused isn't mentally competent.