Dima Sharomov. © Igor Podgorny / Greenpeace

It's dark in Murmansk. A railway security guard yawns, his breath visible in the frigid air, and waves through one of the workers arriving for the early morning shift. He barely glances at him.

Had the guard looked closer, he might have noticed that the worker's face was unfamiliar; that his fluorescent vest wasn't railway issue but bought in a hardware store — that his Valenki boots were brand new. And had he looked in his bag, he might have wondered why instead of ironworking tools there was nothing but a camera with a long lens.

A check of his ID would have revealed that he was Dmitri (Dima) Sharomov, and that he was not, in fact, a railway worker.

Dima was working undercover as a freelance photojournalist commissioned by Greenpeace International. His mission was simple: document the transfer of the "Arctic 30," the 28 Greenpeace activists and two journalists arrested in the Russian Arctic following a protest against Arctic oil drilling, who were being moved by train from a detention facility in Murmansk to others in St. Petersburg.

While the mission was simple, getting the pictures was not. The prison train car had arrived in the marshalling yard, far from the station, and the entire area had been sealed off. To get the pictures you see here, Dima risked arrest, hid behind a pile of coal slag for three hours, and was nearly caught out multiple times in a complex operation. Disinformation and misinformation about plans to move the prisoners had been rife for the week previous, and nobody was sure if in fact the transfer was going to be by train, or by bus; when or even if it was going to happen.

Prison Train Departs for St. Petersburg. © Dmitri Sharomov / Greenpeace

Information had been pieced together from news given to embassies, observations of changing routines, and Greenpeace volunteers who scouted several locations for clues. One Murmansk cabby in particular had been a willing and excellent source of information about official movements. As the likelihood of the transfer and its timing began to solidify, John Novis, head of photography for Greenpeace International, remembers looking into a slim database of photojournalists in Russia who might be available and willing to take on a gig that could — as it did for freelance journalists Denis Sinyakov and Kieron Bryon — land them in jail.

That's when he remembered Dima. Dima and John had both been crew members aboard the Greenpeace ship Esperanza in the South Pacific in 2008. They were there to document and oppose illegal logging and the clearing of ancient rainforests to plant palm trees in Indonesia. Palm oil had become one of the most widely used ingredients in the world for everything from chocolate to cosmetics. The relentless march of monoculture plantations was destroying the habitats of tigers and increasing Indonesia's emissions of CO2.

Dima invited John to share his cabin, which was a big step up from the tiny space he shared with the ship's doctor. As Second Mate, Dima enjoyed one of the few perks of being an officer — a cabin of relatively luxurious standards that he wasn't actually obliged to share. His motive? He was obsessed with photography. He talked cameras, lenses, techniques with John throughout the voyage, showed him his efforts, and invited critique and suggestions.

He'd kept in touch with John over the years with a steady stream of amateur and increasingly professional-quality images.

So when John realised he needed a trusted Russian photographer, skilled in stealth, willing to risk arrest for a Greenpeace cause, he called Dima, who immediately dropped everything and travelled from his home in St Petersburg to Murmansk to join another photographer with whom he split the 24-hour wait for news of the transfer.

When the call came to say vans were on the move from the detainment centre, it was 4 AM. Dima had assembled his makeshift railway workers' disguise, from a lanterned hard-hat to the distinctive rugged boots. He had scouted the area where they expected the train to be and started walking along the tracks. Aside from the danger of being spotted by the security guards around the train, Dima was worried he'd be caught out by other workers on the tracks. He soon realised that none of the workers could see one another's faces as they passed by in the dark, with the bright glare of their helmet-mounted lamps shining in each other’s eyes. He had to keep moving though, and could find no concealed spot from which to take his pictures. Arctic 30 Transported From Murmansk Detention Center. 11/11/2013 © Dmitri Sharomov / Greenpeace

The spot he found wasn't ideal. Guards stood below, and as he saw the vans arriving and raised his camera and 200mm lens to his eye, the dark conditions meant the autofocus took a seeming eternity to lock on the shot. When it did, he was looking through the camera directly into the faces of the distant security guards. He squeezed off a quick set of shots, the sound of the shutter slicing through the night air as if treasonously shouting for the guards to look. He saw the guards squint into the darkness, slid his camera into his bag, and did the best imitation he could of a worker purposefully walking down the tracks.

Arctic 30 Transported From Murmansk Detention Center. 11/11/2013 © Dmitri Sharomov / Greenpeace

The prison car was coupled to a passenger train and prepared to set out for St. Petersburg. It would pass under a railway bridge at the station where Dima had planned to get a second set of shots. But as he walked onto the bridge, he was dismayed to see security guards leaning there. With no excuse to loiter, he asked one of the guards for a cigarette, despite the fact he doesn't smoke. The guard obliged, they made chit chat, and the guards moved down to the platform as the train arrived, leaving Dima alone to again pull out his camera.

Arctic 30 Transported From Murmansk Detention Center. 11/11/2013 © Dmitri Sharomov / Greenpeace

Dima dropped his photos off in the Murmansk support office for distribution, and set off on the next part of the day's plans: get on the train at the next stop. Our volunteer cab driver was more than willing to race the train, and Dima managed to get on and sit at the very back, next to the prison car. On arrival in St. Petersburg, Dima conceived a plan to stay on the train after all the passengers had left, in the hope he'd catch the unloading of the prison car. He hid in the luggage rack, covered in blankets. In the silence of the empty car, a cleaning woman arrived and picked up a blanket, only to see Dima's face. She screamed, which attracted the attention of the station security guard. Outside the train, Dima realised the prison car had been uncoupled, and his vigil had been for nothing. The guard demanded to see his ticket. Dima produced it. The guard looked him up and down, and asked if he had anything to do with the Greenpeace activists who had just arrived. With his camera in his bag and his cover blown, Dima thought it best to come clean. "Da," he mumbled. The guard gave him a conspiratorial look, two thumbs up, and said, "Off you go then. And good luck."

Dima Sharomov. © Igor Podgorny / Greenpeace

No photo agency or wire service was able to get the shots that Dima got, deep in an area cordoned off by prison security guards. But they published his photos, an important record of the ongoing saga of the Arctic 30 and their illegal arrest, around the world.

As funds for investigative reporting dry up and the media landscape flattens into a near- monoculture, watchdog and advocacy groups like Greenpeace have had to pick up work which in the past might have been done by that now endangered species: the investigative journalist. We take on a much more active role in commissioning freelancers to look behind the story, to get the shot, to capture the video, to help the world bear witness to that which some would hide.

Civil society needs to protect the rights of organisations to investigate and expose the truth of environmental dangers like Arctic oil drilling with the same fervor with which the right to a free press should be defended. Both are important tools against corruption and the ability of powerful governments and corporations to hide uncomfortable truths and keep people in the dark, when what's really needed is the glare of a public spotlight.

Journalism, like peaceful activism, is a free people's right — not a crime.

Brian Fitzgerald is Head of Digital Networking & Mobilisation at Greenpeace International.