For reasons unknown to police, theft and burglary crime rises across Auckland in March. It's an anomaly they don't really understand - but they're trying to fight it.
"We don't really know why it's happening, but we know it's happening," Inspector Claire Humble, prevention manager for Waitakere, said of the March anomaly. "But instead of just letting it happen again, this year we're targeting it."
Mrs Humble is heading Operation Vapour, targeting "volume crime" in the Waitemata police district, which began in late February and will run throughout March.
Volume crime includes burglary, breaking and entering, shoplifting, theft from cars and petrol drive-offs - which, for some reason, all rise in March.
The trend, however, isn't a national issue. It appears to be specific to Auckland, predominantly affecting the Auckland and Waitemata districts.
In the 18 months from January 2012 to June 2013, the two March months were up 15 per cent on the other 16 months averaged across the Waitemata, Auckland and Counties Manukau police districts, which make up the Auckland region.
The increase - 20.5 per cent in Waitemata - prompted the launch of the operation.
"We're pooling all our district resources ... all channelled to try and target that volume crime," Mrs Humble said.
Neighbourhood policing teams, road police, frontline beat cops, detectives and Maori, Pacific and ethnic volunteer wardens have all been brought together in a concerted effort to prevent and reduce the offending.
As well as foot patrols and a more visible presence around popular shopping centres, Waitemata police have been increasing road checkpoints on high-use roads and near motorway off-ramps identified as exits often used by recidivist offenders.
Based on district intelligence, police are putting extra staff out on the beat during specific times and days.
"Our deployments are based on our biggest crime days. The days that we are choosing are the days that have been identified as the days with the highest crime risk," Mrs Humble said.
As part of the operation, the Herald was invited along to attend morning checkpoints on two roads in Henderson.
"They're what we would call crime corridors, based on the intelligence we get of where our criminals are," Mrs Humble said at the first checkpoint, on Forest Hill Rd. "That means not only people from this area, but people from other areas too, use it to facilitate their offending."
"It's not about targeting everyone; it's about targeting criminals. We might catch someone who has just done a petrol drive-off or a burglary."
However, the checkpoints were also about "killing lots of birds with one stone", she said, as police not only monitored the drivers and looked for volume crime suspects, but also did their usual checks of licences, warrants of fitness, registrations, diesel kilometres and seatbelt compliance.
After the initial element of surprise - police set up their checkpoints where they can't be seen - the crooks quickly become aware of the sites and share them via text, social media and truck radios, Mrs Humble said.
"By now the criminals will definitely know we're here," she said, after about 30 minutes on Forest Hill Rd. "If you're a criminal, you'll know where we are because your mates will tell you.
"If you stay for too long, people know. The first 20 minutes have the most activity. And then you're mostly getting the public."
But there was some success. In less than two hours on Forest Hill Rd and later on Bruce Mclaren Rd, police made four arrests - three for outstanding warrants and one breach of bail.
They also impounded one car, suspended two drivers' licences, and issued a summons to court for one person driving while forbidden.
One of the vehicles stopped had recently been involved in a petrol drive-off.
There were also 25 tickets dished out for vehicle non-compliance and driving misdemeanours.
The operation is being shared around the district, with targeted officer deployments in different areas across the North Shore and Waitakere.
"I'd say we've probably got 30 more cops visible out on the streets [per operation day] who wouldn't ordinarily be on the streets if we weren't doing this operation."
Van's got your number
Nabbing crooks on the road is easier when you've got cameras which can identify and flag known criminals in real-time.
Waitemata police are using Automatic Number Plate Recognition (ANPR) cameras at roadside checkpoints, to ensure they don't miss an arrest.
A nondescript white van is parked a couple of hundred metres from the police checkpoint. On its roof are two small cameras, pointing in either direction, monitoring traffic.
Inside the van, a screen flashes up a snapshot of every car that drives past. Below the photos, the system generates a digital version of the licence plate image, so technicians can compare and ensure the computer has read the plates correctly.
If a car has stolen plates, or is a stolen vehicle, or the registered owner is wanted by police or the courts, an alert flashes up on the screen. It can also pick up disqualified drivers.
Instead of running a licence plate number through the system manually, the ANPR van did it automatically, said Waitakere prevention manager Inspector Claire Humble.
The data is permanently cleared 48 hours later, Mrs Humble said.
Teamwork brings results
Across the Waitemata district, police from all beats are pitching in to try to curb the anomalous March crime spike.
While neighbourhood and road policing staff were manning checkpoints at "crime corridors" in Henderson, on the morning the Herald was invited along CIB detectives on the North Shore spotted persons of interest and hunted them down.
"It's all about having people in the right place at the right time," Detective Sergeant Steve Pivac said. "We've had our detectives doing patrols. At one of the high-priority locations, a vehicle has driven by and was stopped by police. The car looked suspicious. An officer got a glimpse of the driver, who they suspected was a well-known offender.
"There were two occupants in the vehicle. The driver was a disqualified driver ... and the vehicle had been stolen two days earlier."
The CIB officers ran the occupants' and vehicle's details through their system. But when they returned to the stolen car, the driver sped away.
"We pursued the vehicle for just a short distance but the pursuit was abandoned because we knew we could follow up with him."
The police helicopter was called in to track the car.
"The Eagle helicopter identified the car parked up at a nearby address. Police were directed to that location.
"We found the pair hiding in a wardrobe inside a bedroom."
The couple a 37-year-old man and 32-year-old woman were taken into custody.
"Specifically, this type of policing is not part of our [CIB] core policing role. It's really a whole-of-police approach. It was exactly what we were looking for."