Chris Kahui's defence team is preparing to lodge a complaint with the Police Complaints Authority.
Kahui was acquitted on Thursday of murdering his three month-old babies Chris and Cru in June 2006.
His lawyer, Lorraine Smith, says the complaint will deal with the time it took police to disclose evidence to the defence.
She says the police need to be held accountable, and it cannot be allowed to happen again.
Smith says the consequences for Chris Kahui are horrific, and she doubts he has even begun to grieve for the death of his sons after fighting for his freedom.
The complaint will be laid within the next 10 days.
Meanwhile, those following the case and those investigating it alike are not closer to an indication of who was responsible for the death of the twins.
Children's support agency Barnardos says family loyalty is no excuse for not dobbing in someone who has harmed a child.
Their comments come in the wake of two not guilty verdicts in child abuse cases this week - Kahui 's, and George Gwaze's acquittal on claims that he sexually violated and killed his 10-year-old niece.
Barnardos chief Murray Edridge says it is obvious in both cases someone else knows what happened.
He says everyone can understand family loyalty, but at the end of the day it is a family's role to keep every member safe, and that includes the children.
But the accusations of stonewalling and closing ranks within the Kahui whanau are being laughed off by Smith, who says the whanau co-operated at every stage of the investigation.
She says the finger should not be pointed at them just because
the police could not get their act together.
Smith says Chris Kahui gave a statement to police on the night of
the incident, and three other relatives spoke to police on
more than one occasion.
