Police suspect key people withholding information in Northland baby death investigation

Police investigating the tragic death of a four-week-old in Northland say someone knows what happened - but so far they're struggling with people withholding information.

Just a month ago Maree Ngahere's family was proudly sharing photos of her online. On February 19, the newborn was found dead at a house in Kaitaia.

On Thursday, Acting Detective Inspector Lloyd Schmid revealed the heartbreaking details of her fatal injuries.

"Maree had severe head trauma which caused severe bleeding on the brain that caused death," he told media. "She's also suffering bruises to one arm and the thigh of her right leg."

He said police will do everything they can to find out what happened to the baby girl.

"The full resources of the New Zealand Police will be brought to bear on this investigation and we will get to the bottom of it. We will find the truth on behalf of young Maree."

Oranga Tamariki is working with police as part of their investigation, and police say her family are co-operating, but they're desperate to speak to witnesses.

"Someone knows what happened to Maree, and we're appealing for anyone with information around the circumstances of her death to get in touch with us," Det Insp Schmid said.

New Zealand has one of the highest rates of child abuse in the OECD.  Since Christmas Eve, five babies have been killed or seriously injured in Kiwi homes.

On Thursday a 42-year-old woman appeared in court charged with the murder of one of those babies: a five-month-old killed in Motueka on February 10.

Jane Drumm, general manager of domestic violence organisation Shine, says our child abuse rates aren't getting any better even after high-profile tragedies like the Kahui twins in 2006.

"In New Zealand, if children are going to die, we find a huge percentage of those children who do die or are seriously injured are under the age of two. They are so vulnerable."

Ten days on from Maree's death, police find themselves making a similar appeal, desperate for answers from those who know what happened.