Detective Inspector Mark Loper is giving evidence in the Rotorua District Court as an expert witness for the inquest of Moko Rangitoheriri.
Moko died after being severely beaten by his caregivers in August 2015. He was nearly 3.
Det Insp Loper, who has 32 years' experience in the police, had overall strategic supervision of the homicide investigation Operation Corsa.
He was also the officer-in-charge of the murder of Nia Glassie in 2007, another horrific child abuse case that has drawn parallels to the death of Moko.
In the eight years between the two toddlers' shocking deaths, 94 children were killed, according to police records.
Since Nia died, Loper said police had made significant changes to how child abuse cases are managed and investigated.
• Dedicated child protection teams in each area.
• More detectives to investigate reports of child abuse.
• Child protection teams are physically located with Child Youth & Family (now the Ministry for Vulnerable Children, Oranga Tamariki) for greater collaboration.
• Extensive training for investigators.
• Child abuse is a top priority for the district commanders.
There has also been a cultural shift in the police, said Loper, and staff now look at the wider environment of the family home and focus on the needs of the victim.
"Most of the offenders are from within the family and it is not unusual to find other family members also have knowledge that offending is occurring," said Loper.
The "Family Harm Project" is a more holistic approach and does not solely concentrate on violence and sexual offences but considers alcohol and drug abuse, unemployment, poverty, parenting skills and controlling behaviours.
It also involves collaboration with agencies such as Corrections, Oranga Tamariki, Health, Women's Refuge and ACC.
Together, the agencies can assess the risks and ensure the right referrals for help are made.
"The focus is on identifying the underlying cases of family harm so that interventions can be put in place to address the many issues facing whanau today."
Under questioning, Loper said prevention was at the forefront of "everything we do". He confirmed the Family Harm Project was on a trial basis but it was hoped to be rolled out nationwide.
Moko's killer, Tania Shailer, and her partner, David Haerewa, were jailed in June 2016 for 17 years with a minimum non-parole period of nine years after pleading guilty to manslaughter.
They appealed their sentences, saying they were too harsh. But the Court of Appeal rejected the bid and said the pair should count themselves "fortunate" they were not jailed for life.
