Kahui case gets stronger

Police say the prosecution case against the killer of twin boys Chris and Cru Kahui is "getting stronger and stronger each and every day".

The head of the investigation, Detective Senior Sergeant John Tims, said as police gathered more evidence, the skeletons of the family and their associates were being exposed.

The police inquiry into the deaths of the twins is now heading into its seventh week with still no sign of an arrest. Efforts to find the killer have been hamstrung by a lack of conclusive forensic evidence and co-operation on the part of the so-called Kahui "Tight 12".

Now speculation is mounting that without a confession from the killer, police may never get the evidence they need to establish a prima facie case.

The twins died in Auckland's Starship hospital on June 18, from injuries including broken ribs, brain damage, and a broken thigh bone.