Ana Kriegel's father declared that "justice has been served for Ana" following the sentencing of the two boys for murdering the 14-year-old schoolgirl.
Speaking outside the Criminal Courts of Justice, Patric and Geraldine Kriegel thanked Inspector Mark O'Neill and the members of An Garda Siochana who had "put everything they had into finding those responsible for Ana's murder."
Geraldine also thanked the jury, trial judge Justice Paul McDermott, prosecution counsel Brendan Grehan SC, the media, their family, friends and neighbours.
She added: "Thank you to all of the wonderful people out there who supported us and kept us going."
Patric said: "Justice has been served for Ana. The judge has decided on the sentence and that duty lies within law.
For our part, we can only say that forever is not long enough.
"Please remember Ana and keep her in your hearts somewhere."
Superintendent John Gordon said the trial had "raised many questions for many people about the care of our young people in society today and we would like to bear in mind at this time that the role of the protection of our young people is not just a matter for An Garda Siochana but each and every one of us."
The superintendent added: "Our thoughts today are with the Kriegel family, with Geraldine and Patric. We would like to extend our sincere sympathies to the family and to their extended family who have borne this trial with great dignity.
"This was a very difficult and complex case and we would like to acknowledge the support and help of the community at this time, without their help we wouldn't be in the place we are today."
He further acknowledged the role of members of the gardaí under the leadership of Detective Inspector Mark O'Neill and Chief Superintendent Lorraine Wheatley.
He said: "It was very important they all worked together and dealt with this case to a very high degree of sensitivity. It was a very complex case which required a very considerable amount of resilience and each and every one of them stepped up to the mark and I would like to acknowledge that."
Boy A was sentenced today to life with a review after 12 years for murdering Ana at an abandoned house at Laraghcon, Clonee Road, Lucan on May 14, 2018. He was sentenced to eight years for Ana's aggravated sexual assault.
Boy B was sentenced to 15 years with a review after eight years for Ana's murder. Now aged 15, both boys were convicted by unanimous jury verdicts earlier this year.