And Children's Commissioner Cindy Kiro said today she hoped someone was held accountable for the murders.
Dr Kiro said it would be deeply distressing to many New Zealanders if no one was held accountable for this crime.
She called for members of families "on the fringe of society" to break the wall of silence when the police came to call.
"Three-month-old babies cannot speak for themselves. Someone needs to break rank and tell the truth."
After the twins' father, Chris Kahui, was found not guilty of murdering his sons by a jury of seven men and five women in the High Court at Auckland today, police confirmed the case would be closed and no one else would face any charges over the babies' deaths, including their mother Macsyna King.
The officer in charge of the case, Detective Inspector John Tims, congratulated the jury on the decision today but when asked who got it wrong - the jury or the crown and the police - he refused to answer.
In August, 2006, Mr Tims said the fatal injuries inflicted on Cru and Chris were not an accident.
"Make no mistake. This is a double murder investigation," he said before police arrested Chris Kahui and charged him with murder.
He was asked today, now that police would not charge anyone else over the babies' deaths, did that mean someone had got away with murder.
"The murder investigation has been concluded by the decision of the jury today," he responded.
"It is a double murder to be honest," Mr Tims said.
"So someone has got away with murder. There is no one been held accountable?" he was asked by NZPA.
"There has been no one held accountable for the death of Chris and Cru Kahui," Mr Tims said.
He said the evidence had been taken to court and the jury had made its decision. He was asked again what went wrong.
"I can't answer that question to be honest. The file has been reviewed. I have reviewed the file. I have looked at it. We have gone over and over it with the evidence. The great thing about it is that the jury has heard all the evidence and has come up with the answer."
Mr Tims said several times no new evidence was produced during the trial to support a charge against Macsyna King or anyone else.
"The defence did not bring any new evidence to the table. The evidence they brought to the trial was straight from the investigation file."
During the trial, defence lawyer Lorraine Smith said the evidence pointed to Macsyna King inflicting the fatal injuries and not Chris Kahui.
Mr Tims said each person who was at the Kahui house was a suspect after the babies died.
"We thoroughly investigated each person until we identified Chris Kahui and made the arrest."
Mr Tims congratulated the jury for its decision.
"The jury system is the system we have in New Zealand and this is the type of case that should be heard by a jury.
"There are 12 people who have heard all the evidence and they have made a decision and that is a decision we must all abide by."
He said the crown advice and medical evidence indicated Chris Kahui was the murderer and for that reason he was arrested.
"But the jury has listened to the evidence and acquitted him."
He said the police had no reason to revisit any of the evidence.
"As far as I am concerned the matter is closed. The jury has made its decision."
