Earlier on Thursday, a jury of 11 members – nine men and two women – as well as four reserves were sworn in.
The jury selection process began in private on Monday under the direction of the coroner Mr Justice Rooney.
About 100 members of the public were in court for consideration as potential jury members at the beginning of a protracted and thorough process.
The number was eventually reduced to 23 people, and then after one further excusal, 22.
The 11 jury members were then drawn by ballot from the group of 22.
Fiona Donohoe watched on as the jury members were sworn in individually.
Mr Justice Rooney told the members of the jury it “is a very difficult day for her”.
He said she had to wait some time for the inquest to begin and the coroner then gave a brief overview of the schoolboy’s disappearance and death.
He also warned the jury members that they must reached a verdict based only on the evidence they hear at the inquest.
The inquest is continuing.