1.

It’s been a tough year, but Mellory Manning’s turning things around. These days she’s steering clear of the people, places, and habits that have given her so much trouble.

Mellory is twenty-seven, and she’s kind of striking: a wide forehead, high cheekbones, thick, curly auburn hair. The people who know her around Christchurch know she’s loyal to those close to her — a sympathetic listener, a friend. But life’s not simple, and Mellory’s got difficulties of her own, not least a longtime drug problem that she pays for with sex work.

Then, in August — the middle of wintertime in New Zealand — Mellory’s older sister Jasmine kills herself. The loss is a jolt. Her life’s on a downward slide, she realizes, same as Jasmine’s. It’s enough to catalyze a change: She quits the street, goes clean, starts thinking about the future. Maybe she’ll go back to school. She talks to her boyfriend about starting a family. But when Christmas arrives, Mellory’s down again. Short on money, she sees no option but to hook again. One last night.

On the evening of December 18, 2008, Mellory stands beneath the old oak at the intersection of Peterborough and Manchester, a crossroads just north of downtown Christchurch. It’s the same corner she’s been working for years. It’s summer. She’s in a pink miniskirt, blue bikini top with polka dots, a thin gray sweater, and a hooded cardigan over the top.

Mellory meets at least two customers that night. The first man drives her to the parking lot of a vacant hotel just a few miles away. The second encounter happens at around 10:00 p.m., in another nearby parking lot. It doesn’t take long: By around 10:20 p.m., she’s back at her corner.

Eight minutes later, she gets a text message from the client who just dropped her off. He writes:

See you again sometime for mutual fun.

She replies.

We will one day.

The next morning, a kayaker paddling through the shallow waters of the Avon River spots something entangled in the branches and grass along the riverbank. It is Mellory’s body. The autopsy reveals that she has been strangled, beaten with a metal pole, and stabbed three times before being dumped in the river.

The chief investigator on Mellory’s case was detective Greg Williams, a tall, brawny fifty-two-year-old who wears wraparound sunglasses. The killing put Williams, like the rest of Christchurch, on edge. Two other prostitutes had been murdered in the previous couple of years. Without a swift indictment, the community would inevitably start whispering about a serial killer, even though the police never thought the murders were connected.

Williams also knew the numbers were against him: Only a tiny number of investigations of murdered sex workers result in successful convictions. There are plenty of reasons these cases are difficult to solve, and some of them are understandable: the work itself, which happens in the shadows; the intimate interactions with many potential suspects; the complicating factors of alcohol and drugs.

But Williams chafes at the suggestion underlying those numbers — that society values some lives less than others. He set out to prove that such callousness, deliberate or otherwise, has no place in his department, or for that matter in his city. To find whoever murdered Mellory, Williams spearheaded what would become one of the biggest and most expensive forensic investigations in New Zealand’s history.

Cell-phone data and witness information helped paint a detailed picture of Mellory’s movements that night, providing police with numerous leads to pursue. There were the two clients, of course, and a Ford Falcon in the area that the cops wanted to know more about.

After meeting her second client, Mellory was picked up in another car at 10:40 p.m., and she sent that final text message at 10:43 p.m. Water damage to her watch caused it to stop just before 11:00 p.m., which corresponded with a witness report of a loud splash in the river at roughly the same time.

The medical examiner found small scratches on Mellory’s body that indicated contact with prickly vegetation. Analysis of plant material on her clothing suggested that she had come into contact with an area dense with weedy grasses. And the fact that the exit wounds on Mellory’s back were small and similar meant that the knife used to kill her likely hit against a hard surface. He also noted that Mellory’s left arm was probably positioned up and in front of her head when she was murdered, a reflexive act of self-defense.

Williams dispatched officers to examine dozens of sites around the city where Mellory had been or might have been in the weeks prior to her death. He also made sure he wasn’t missing anything in the river itself. Instead of the typical procedure of using oranges to determine how far the body might have floated, Williams had investigators build two adult-size plastic dummies so that he could more accurately model how Mellory’s body had traveled.

In the months that followed, hundreds of people were interviewed by the police, and suspects’ names were gathered, chief among them the members of a local gang, the Aotearoa Mongrel Mob. The group was financed by drug money and prostitution. Sex workers in Mob territory have to pay a protection fee, and one hypothesis was that Mellory had defied Mob members and was killed as punishment.

In the neighborhood where Mellory’s body was found in the river, the Mob rented a hybrid garage/warehouse, as well as the overgrown vacant lot next to it. Located on Galbraith Avenue, the 1.5-acre property is just a short walk — perhaps four hundred yards — from the edge of the river.

The Mob connection was a reasonable guess, nothing more. The police redoubled efforts to pinpoint the location of the murder in the hope that it would shake loose new information about a perpetrator. But the case was stuck. Williams’s best shot now was a breakthrough by the pollen detective.

2.

An Expert In The Invisible