Gardaí who investigated the shocking murder of Ana Kriegel described the case as “unprecedented.”

Speaking at a press briefing following the sentencing of Boy A and Boy B on Tuesday, Superintendent John Gordon was direct and to the point.

“None of us have seen anything of this nature in our time and hopefully will never see anything of its nature again,” he said.

The two teenage boys had earlier been sentenced for Ana’s murder last year.

Now aged 15, they were convicted in June of murdering Ana, thus becoming the youngest murderers in the history of the State.

Boy A was sentenced to life in detention, with his sentence to be reviewed in 12 years.

Boy B was sentenced to 15 years for his role in the murder, with his sentence to be reviewed after eight years.

The boys were aged 13 when they killed Ana in a derelict house in Lucan.

Boy A also sexually assaulted her.

He was given an eight-year sentence for the sexual assault to run concurrently with the sentence for murder.

The lead investigator on the case, Detective Inspector Mark O’Neill, said establishing a motive was vital as soon as they suspected Ana had been killed by other children.

 “I think you always want to find out why when you investigate any serious case, but even more so in this particular case,” he said.

“Unfortunately, we weren’t able to in this case and we still don’t know why.

“But the investigation team were dedicated and committed to solving it and they did that.”

Supt Gordon said several “special arrangements” were put in place once gardai knew Boy A and Boy B were suspects in Ana’s disappearance.

“They started when the case first became a missing person case in Lucan,” he said.

“Ana was first reported missing initially to Leixlip Garda Station.

“She was 18 hours missing when Lucan first became aware of the missing person case.

“From the time she went missing it became very obvious that something was awry.

“I met Ana’s parents, Geraldine and Patric, in St Catherine’s Park on the afternoon of May 15.

“They were devastated at that time, above and beyond an ordinary missing person case.”

Superintendent Gordon went on to explain how the investigating team worked.

“The search continued for three full days,” he said.

“Ana had missing person status up to and including May 17, when her body was discovered.

“From there suspects were identified, and as we know now they were Boy A and Boy B, who were 13 years of age at the time.

“I had met Boy A and Boy B and they presented as the last persons to have seen Ana.

“As things moved forward they were identified as actual suspects.

“As the court kept pointing out they are juveniles and have that entitlement to their anonymity.

“By default their families are also entitled to that.

“It was deemed necessary at the time of arrest that stations other than Lucan would be used and the boys would be housed in different stations so Blanchardstown and Clondalkin were made available to us.

“Those stations were cleared out from midnight the night before so that there were no other prisoners in there.

“We had free access to both those stations from late May.”

As the case unfolded in the months following the boys arrest over 500 lines of inquiry were investigated, over 500 statements were taken, 250 exhibits were seized and examined, and up to 700 hours of CCTV was examined.