Helicopter pilot Roger Gower swooped low to get close to the fresh elephant carcass, which lay in the thick bush of Tanzania’s Maswa Game Reserve.

The people who had killed the huge animal were nowhere to be seen, according to National Geographic. But its ivory tusks were still intact, so the poachers had to be around somewhere.

Gower and his safari guide scanned the area, the “thwack, thwack” of the helicopter’s rotor loud in their ears. Then they saw it: a pile of ivory perched atop a small hill.

The poachers knew they’d been spotted. They emerged from their hiding place in the bush and fired on the helicopter with an AK-47, Tanzanian member of parliament Lazaro Nyalandu said on Twitter. At least one bullet cut through the floor of the helicopter, hitting Gower’s leg and shoulder and then piercing the roof, a colleague told National Geographic. Though Gower was able to land the craft, he succumbed to his injuries before help could arrive. The veteran British pilot died Friday at age 37; his co-pilot survived with injuries.

“This tragic event again highlights the appalling risk and cost of protecting Tanzania’s wildlife,” the Texas-based Friedkin Conservation Fund, which runs some anti-poaching operations in the country, said on its website.

On Monday, Tanzania arrested three suspects in Gower’s killing, according to the BBC. Pascal Shelutete, a spokesperson for Tanzania’s parks, said that authorities found three elephant carcasses in the area.

“Whoever shot the chopper down was on a serious illegal hunting spree,” he said, and were probably “heavily armed with sophisticated military weaponry.”

This is the case across Tanzania and much of Africa, where illegal hunters are armed to the teeth and anti-poaching efforts can be as deadly as all-out war.

It’s difficult to know how many people have been killed in the bloody battle over Africa’s wildlife, but the human toll is high. The Thin Green Line, which helps train park rangers and anti-poaching personnel, estimates that 1,000 rangers have been killed in the line of duty in the past 10 years, three quarters of them by commercial poachers and armed militia groups.

There’s also the psychological toll of the constant combat. Rangers who continually find themselves dealing with the carcasses of dead animals, or in life-or-death confrontations with armed poachers, suffer the same scars as soldiers at war.

“This is a guerrilla warfare situation being fought by men and women trained to protect animals and not trained to kill,” Rethea Fincham, a clinical psychologist who treats rangers at Kruger National Park in South Africa, told National Geographic in 2014. South African National Parks requires that rangers see a psychologist after any direct engagement with a poacher.

Johan Jooste, special projects commander with SANParks, described the effect simply:

“It’s a relentless onslaught,” he said.

The fight over illegal hunting is just as dangerous to the desperate people on the other side of it. Elephant poaching is high risk but high pay-off, and increasingly controlled by organized crime networks that supply poachers with military-style weapons. The actual dirty work is done by mostly poor, mostly desperate foot soldiers who have few other opportunities to make as much money as the ivory dealers are offering. In exchange, the crime syndicates get ivory that fuels a global black market worth hundreds of millions of dollars.

“This is a huge amount of money,” conservation biologist George Wittemyer told The Washington Post in 2014. “A big male elephant can have 40 kilos [about 90 pounds] per tusk. You’re talking about big time dollars. Even in the U.S., we’d have issues with [poaching], and these elephants are in poor areas. So there’s a lot of pressure.”

“It’s poverty,” agreed Arnié Ngoveni, who lives near Limpopo National Park in Mozambique, in an interview with Al Jazeera last year. “Mostly young men go because they need money, and they go there to risk their lives. I don’t like poaching because sometimes the men die, and it’s not good for the families.”

Ngoveni’s grandson was killed while hunting in the park illegally last year. He left behind two wives and nine children.

A song written by a local DJ — banned on Mozambique state radio but popular in clubs — addresses local park rangers, according to Al Jazeera: “What is wrong with you?” the lyrics go. “… Our children are dying. You are killing our people.”

Caught in the middle, of course, are the elephants themselves. A June 2015 census found that Tanzania’s elephant population has fallen 60 percent since 2009, according to Quartz. In Mozambique, the elephant population dropped by roughly half.

The Environmental Investigation Agency, a conservation watchdog group, published a report in 2014 arguing that corruption, official collusion with illegal ivory dealers, the proliferation of weapons and a lack of enforcement were dooming efforts to protect Tanzania’s elephants.

There are really good people on the ground sweating blood to try and stop this, good people with real soul and concern about what’s happening to their resources,” EIA Executive Director Mary Rice told National Geographic. “But they’re being undermined by a system that repeatedly fails them.”

The country has seen something of a turnaround in the past year and a half: In December 2014, Tanzania arrested a Kenyan businessman said to be the “most wanted ivory smuggler” in the country. It made several more high-profile arrests in 2015.

Wayne Lotter, a director with the nonprofit PAMS Foundation, which supports anti-poaching efforts in Tanzania, told National Geographic that poachers are under increased pressure now.

“We’re at a point where there are more rangers out on the front lines, and that increases the risk of something like this happening,” he said of the fatal shooting Friday.

An African elephant grazes in Tarangire National Park on the outskirts of Arusha, northern Tanzania. (AP/Mosa’ab Elshamy)

Gower had been working on anti-poaching efforts for about a year before he was shot. Born and raised in Britain, he’d worked as an accountant until 2009, when his sense of adventure pushed him to get his helicopter pilot’s license.

That brought him to Tanzania, where he was hired by a luxury safari company to escort wealthy clients and celebrities around the country’s safari circuit. He did that for five years before joining the Friedkin Conservation Fund, where he helped carry out anti-poaching patrols and flew Friedkin staff between various camps on the Maswa Reserve, Pratik Patel, a director at the Friedkin, told National Geographic.

“He was totally passionate about working to make a difference in conservation and helping with this huge global fight” against poaching, Patel said.