Police fired a record 46 rounds in the Kawerau siege, but could have used tear gas or dogs instead of breaking into the house
The Kawerau siege was the biggest police shootout in New Zealand's history - but a chain of mistakes meant the AOS could have used tear gas or dogs instead of raiding the house where four officers were wounded.
Members of the Rotorua Armed Offenders Squad fired 46 rounds inside the house after Rhys Warren shot at them, which is the most ever according to available records.
By comparison, police fired four shots at David Gray during the Aramoana massacre.
Firing 46 rounds was "astonishing", according to a former expert police negotiator, and the injured officers were "lucky to be alive" after entering the house in Kawerau in March last year.
The AOS were hunting for someone who shot at a police plane looking for cannabis plots, but the raid ended in disaster with four officers injured in the gunfight.
The 22-hour siege ended with Rhys Warren surrendering peacefully. He was later convicted of six charges, including two of attempted murder, and is due to be sentenced in the High Court at Tauranga in August.
But an internal police report, released under the Official Information Act, reveals a string of mistakes which influenced the AOS decision to enter the house instead of flushing him out with dogs or tear gas.
The AOS Commander was not told critical information about the shooter's behaviour or activity at the house; a "communication vacuum" which changed the chosen tactics with unintended consequences.
There was also confusion about the different roles in the Rotorua AOS leadership, as well as oversight from the regional communication centres, and the district and national command centres.
Officially, Inspector Anaru Pewhairangi was the AOS Commander or Zero Alpha.
However, Pewhairangi lacked the current training certificate so control was handed to Senior Sergeant Denton Grimes, a 20-year AOS veteran.
In giving evidence at Warren's trial, Grimes said no one had answered the landline phone at 158 Onepu Springs Rd, or reacted to the loudhailer, or rocks thrown on the roof of the house.
After several hours of unsuccessfully trying to get a reaction from anyone inside, Grimes said the option of using tear gas was discussed and discarded.
This was because they were still uncertain if anyone was inside the address, such as a child or elderly person, so Grimes did not believe the legal threshold to use gas was met.
The next step was a "Close Target Reconnaissance", or CTR, where the AOS moved up to the house to check the entry points and look through the windows to see if anyone is inside.
In this case, the AOS smashed the windows of the house and removed the windows.
No one was seen inside, so Grimes authorised the team to clear the address.
About 10 minutes later, "shots fired, man down" was heard on the radio.
Two officers were injured by shrapnel; but more seriously Regan Mauheni was struck in the skull by bullet ricochet and had to be dragged to safety.
Sometime later, Logan Marsh's hand was "blown off the gun" he had trained on the house.
Miraculously, the bullet struck him in the middle finger of his right hand, travelled through the hand and finally lodged in the magazine of the rifle.
According to the internal police review, there was "considerable self-reflection and acknowledgement that aspects of the Operation Pencarrow tactical plan were not optimal".
The decision to smash the windows and remove curtains to see inside the house "did not conform to accepted CTR practices".
It also meant the AOS could not send dogs into the house - considered the most effective way of finding an offender - because the broken glass would cut their feet.
As a result of the Kawerau siege, protective boots are required to be available for AOS dogs.
Also, the report found there was "insufficient understanding/clarity" around using tear gas to clear the address instead of going inside.
In response to Weekend Herald questions, Inspector Jeff Jago said the use of gas would have been legally justified "based on all information that is now available".
"Ultimately, these situations are often complex and dynamic. Circumstances can and do change very quickly and decisions have to be made based on the information available to officers at the time.
"As this was an unfolding incident not all information was readily or initially available to the AOS Commander which ultimately influenced decisions that were made on the tactics to be adopted," said Inspector Jago.
"It is now recognised that the "Close Target Reconnaissance" undertaken had unintended consequences which then influenced decisions to not deploy CS gas, or not deploy police dogs into the house."
The Independent Police Conduct Authority is also investigating and is expected to release another report this year.
'Air of panic'
Lance Burdett, a former police crisis expert who handled negotiations with Jan Molenaar during the 2009 Napier siege, analysed the review document to provide comment.
He said there was no clear line of command, with different officers having input at different stages, sometimes simultaneously.
In his opinion, sending in a police dog - which are trained to enter a house and bark when someone is found, then called back to the handler - and using tear gas were clearly the best options.
Firing 46 rounds was "astonishing", said Burdett. The officers were firing "in the direction" of Rhys Warren, according to the report, which Burdett said had the "air of panic about it".
This was because the AOS, which is a part-time role, train with targets or video screens, as opposed to special forces who train with actors who fire back.
"Suppressive fire is used to pin a person to a location when they cannot be seen," said Burdett.
"However, I would question the use of suppressive fire in a residential location and that it would seem to be random firing rather than directed discharging."
Unintended consequences from Operation Pencarrow
• Significant details about shooter's behaviour and activity were not communicated to AOS Commander, which impacted decision making.
• Decided tear gas could not be legally justified, when it was.
• Smashed windows to look inside house, which was not best AOS practice.
• Broken glass meant AOS could not send in dogs, as they did not have protective boots.
• All AOS dogs now have access to boots.