Details of the sexual offending have been suppressed but may be revealed at sentencing.
Justice Lang will decide at sentencing whether the details stay suppressed or if they can be published.
The Crown will seek preventive detention for Stroobant and cited public safety issues.
Stroobant was supported in court by family members. As he left the dock a woman believed to be his mother put her hand up to the glass, and he put his hand against it. They spoke softly to each other as he was led out the door to the cells.
Stroobant was silent during the hearing, uttering just three words - a guilty plea to each charge.