Constable Ben McLean shot dead his wife, Verity, while she was bound and gagged. He then twice shot her new partner Garry Duggan. He later told Verity's father: "She wouldn't talk to me or have anything to do with me and I snapped."

Appearing in the High Court at Invercargill on Thursday, Benjamin Peter McLean, 48, a police officer for 10 years, pleaded guilty to the murder of his wife Verity and the attempted murder of her lover Garry Duggan on April 25 this year. He will be sentenced on December 18. MARTIN VAN BEYNEN reports.

Invercargill cop Ben McLean had his face in the gravel and his gun had just been broken over his head.

His plan to kill his wife and her new partner and make it look like a murder/suicide was in desperate trouble.

ROBYN EDIE/STUFF Constable Ben McLean has admitted murdering his wife, Verity, and the attempted murder of his friend Garry Duggan. He entered the guilty pleas in the Invercargill High Court on Thursday morning.

Although his wife Verity McLean was dead, the two shots he had fired at her new partner Garry Duggan had failed to knock him down and Duggan was a fighter.

Duggan had managed to wrest the cut down, bolt action rifle from McLean and smash him over the head, the stock parting company with the barrel. In the frenzied ensuing struggle, Duggan managed to ram his former friend's head into the rough gravel of the builder's yard where he and Verity had been living since Verity left McLean on April 5, this year. She and McLean had been married for 18 years and had three children.

McLean had another trick up his sleeve and grabbed a 50-centimetre wooden baton from a backpack and stunned Duggan with a strike to his forehead.

FACEBOOK Verity Ann McLean was killed by her estranged husband on April 25, 2017.

Duggan was bleeding from wounds caused by the two shots, one of which had gone through his upper stomach, his liver and his kidney, and the other into his left forearm.

He now found himself in a choke-hold with McLean behind him but somehow managed to grab the baton and, hitting backwards over his left shoulder, succeeded in breaking McLean's hold and hit him in the knee caps.

Both men, who had been friends for 15 years and whose families had gone on holiday together, were spent and they argued as they rested on the gravel together.

SUPPLIED Garry Duggan wrestled the gun off Ben McLean despite being shot twice.

"You better not have hurt Bert," Duggan said, referring to Verity.

McLean said she was at a friend's place, but Duggan could see the light on in the flat window where Verity would normally be standing when he came home from work.

He forced McLean down the long driveway leading to the yard's entrance, striking him a few times with the baton and McLean climbed the 1.8 metre-high gate to fetch his mountain bike from the truck wreckers next door.

He then spent a few minutes talking to Duggan, who had remained at the gate, and then rode away. Duggan called 111.

Verity's bruised and beaten body was propped up on the couch in the flat. She had been bound and gagged and shot under the chin.

McLean cycled away and rang his 16-year-old son whom he had earlier that day taken to Dunedin with his younger 9-year-old brother to stay with their aunt.

NICOLE JOHNSTON/STUFF Ben McLean started in the police in 2007 and did a range of duties including traffic safety.

The call was timed at 8.22pm. He told his son about shooting his mother and said he was sorry.

The aunt then took the phone and McLean told her: "I have f...ed everything. I'm f...ed. I went around and shot and killed Bert and shot Garry. He got hold of me and has beaten me really bad. I'm on the run.

"I've killed her. I don't know why I thought it was a good idea."

MARTIN VAN BEYNEN/STUFF Verity McLean brought her chickens with her when she and Garry Duggan moved to a flat in an industrial area of Invercargill.

A few minutes later he called his daughter, 19.

He told her he was sorry and had killed her mother, shooting her in the head.

It appears McLean put his plan into action when he returned from Dunedin about 5.30pm. While he was in Dunedin, Verity rang him to say she had broken into their Invercargill house by smashing a window and taken her things.

MARTIN VAN BEYNEN/STUFF Police alleged Constable Ben McLean came through the entry door of this back unit to accost and later shoot his wife Verity.

She had arranged for a glazier to fix the window next day. They had another heated talk on the phone about 2pm and McLean hung up.

When he got home he reviewed footage from a CCTV camera set up at his house. The footage from earlier in the day showed Verity making an insulting hand gesture as she left the house after breaking in.

In the early evening McLean, who held a firearms licence, dressed in black and donned a backpack containing the Plinker rifle, a long baton, disposable rubber gloves, a pair of black police issue plastic handcuffs, hand sanitiser, towels and a New Zealand police portable radio tuned to the frequency of the main Invercargill police communications channel.

MARTIN VAN BEYNEN/STUFF Verity McLean and Garry Duggan, were shot at the back of an industrial buiding in Otepuni Ave, on the outskirts of Invercargill.

Any identifying marks had been removed from the rifle, which was fitted with a silencer from one of his other rifles. The origin of the cutdown, single shot, bolt action rifle remains murky but it appears McLean bought it through the internet.

McLean had set up a false alibi by arranging for the CCTV camera to record him being home at a particular time. He then left the house for the shootings by a back way, to give the impression he had not left his property that evening. He then rode his bicycle to the industrial area where Verity was living.

Verity and Duggan began having an affair in December 2016 and McLean confronted his wife about his suspicions on April 5, 2017. The marriage had been rocky and Verity had had other affairs.

MARTIN VAN BEYNEN/STUFF Verity McLean was shot in a small unit behind this workshop building at 66 Otepuni Ave (pictured) near the centre of Invercargill.

She told him she was leaving him for Duggan and moved into a flat at the back of a bleak building in Otepuni Ave in Newfield, an industrial area about a 5-minute drive from the McLean property. It belonged to Duggan's friend Phil Brocks, a fencing contractor.

Between 6pm and 8pm on April 25, McLean arrived at the flat where Verity was alone and cooking a meal. Duggan was due home about 8pm. The evening was cool and Verity had lit a fire in the log burner.

McLean overpowered her and bound her with the police issue ties. Finally, he shot his wife under the chin as she sat tied and gagged on a couch. He then removed the ties and the gag and put the ties in the wood burner. He could not however remove the 36 bruises on her body caused by a blunt instrument.

He then waited for Duggan, who arrived home from work at 8pm and parked his car.

As Duggan was walking away from his car, McLean appeared from behind Verity's Holden Commodore and said "Garry". Then his plan fell apart.

After the shooting, his daughter's boyfriend and his mother took him to the police station. On the way he told them he had "messed up" the family and his children would never talk to him again. He was taken to Invercargill Hospital and treated for a significant cut to his head. He has not provided a statement to police.

BUBBLY, DOWN-TO-EARTH WOMAN, A WONDERFUL MOTHER

Ben and Verity McLean had been raising three children at the time of the shootings and had been long-time friends of Duggan and his wife Rachel. The families took trips away together. McLean had taken a few months off police work earlier this year and worked at the Tiwai Point Aluminium Smelter as a fireman.

McLean and Duggan, a truck driver, also ran a firewood business together from the McLeans' 1.8-hectare section on the outskirts of Invercargill. Ben McLean's mother, Mary Poulsen, lived next door on a 1ha block.

Friends say Verity was a bubbly, down-to-earth woman and a wonderful mother. She came from a well-known Invercargill sporting family. Her father, Bob Barber, was an All Black and a Southland rugby stalwart. He and his partner had an emotional meeting with Ben McLean in prison a week after the shootings. Their estranged son-in-law told them he was sorry. "She wouldn't talk to me or have anything to do with me and I snapped."

Before McLean joined the police, he taught at a Southland high school and worked as an administrator for Geographic Information Systems.

Although they presented a wholesome image to the outside world, the McLeans' marriage was rocky. One family friend called them a role model family, but others who knew them said the description was misleading.

The McLean children went to Verdon College, which was only a short bike ride from their Scott St home. Their parents were well regarded and active members of the Catholic school's community who could be counted on for fundraisers and other school activities.

McLean was a clever amateur engineer and had made much of the equipment for the firewood business himself. He had a bent for machinery and was keen on classic cars. An old Chevy and a Holden were gathering dust in his garage, awaiting restoration.

Friends say he was a hard worker, but had a habit of starting things and not finishing. The house in which he and his wife had lived was not a plush affair. He had built a large lean-to on the side of the double storey house and clad it with used corrugated iron and plywood.

As a police officer Ben McLean was regarded as unflappable and hard to upset.

"He was a very relaxed guy. When we heard about the shooting it was like a bolt from the blue. He was the last person you would have expected to do something like this," a police colleague, who did not want to be named, said.

"He wasn't aggressive and when we were out, it was very difficult to push his buttons."

Despite a placid exterior, he was not retiring when it came to the physical stuff of police work, the mate said.

The flat in which Verity was killed was in the back of an old, rough cast warehouse-type building on Otepuni Ave, about 5 minutes drive from the centre of Invercargill.

She had brought her chickens and they had the run of a muddy enclosure at the side of the building.

The flat looked out onto a large yard, containing stacks of timber, containers, sheds, piles of firewood and building equipment.

Surrounded by mainly truck wreckers and similar businesses, the area was deserted on the Tuesday night Ben McLean rode to the address. A railway track ran behind the yard and over the road was the Otepuni Stream and walkway.

In many ways the area was tailor-made for an unheard and unseen crime. But even the best plans come unstuck and Ben McLean will bear the consequences.

The Barber and McLean families said after court that the shootings were "not just another story".

"It is real life and we have to live it on a daily basis," they said in a statement.

"This has been a very difficult year for us all and as Christmas approaches we are all going to find it a tough time, but will get through it together with the support of those around us.

"We believe that Southlanders are decent, family-oriented people, who would understand our need for privacy and sensitivity, especially for the [McLeans'] children."