This coolly even-handed documentary dips into the lives of an ivory poacher and a stressed-out wildlife ranger trying to obstruct the illegal trade

Jon Kasbe’s documentary When Lambs Become Lions has been much praised on the festival circuit, and it is cleverly and effectively made, seeking to grip you the way a thriller would. Yet I’m not sure that I was completely on board with this film, which appears to have smoothly carpentered its narrative in the edit. Is it almost too good to be true?

The film gives us a coolly even-handed study of some ivory hunters in Kenya – and also the rangers, the hunters of the hunters, who have to roam through the landscape, in their camouflage gear and assault rifles, on the lookout for those who are illegally killing elephants for their tusks.

On the one side, there is a poacher, whom Kasbe has agreed simply to call “X” – an understandable consideration, but one that in journalistic terms obstructs any attempt at independent verification of the story being told. He is working with an assistant called Lukas, who does the dirty work by killing the animals with poison-tipped arrows. (There is also talk of poaching with larger teams, but this film concentrates on X and Lukas.)

On the other side there is a ranger, Asan, who like his comrades hasn’t been paid for months and has the pressures of a new family. He is also a cousin to X, and knows all too well how richly rewarded poaching can be, compared to being honest. As someone says: “Ivory money and ranger money – there’s no comparison.”

Are the temptations going to be too great? Kasbe appears to have spent time “embedded” with both sides, evidently without telling the good guys what he knew about the bad guys’ plans. Or has the film been teased out of the existing back channel between X and Asan?

There is a persistent and slightly exasperating obtuseness here, common to many documentaries about poaching. How about investigating (or mentioning) the customer? X talks about “the buyer”, but that’s as far as it goes. Is it someone in the far east? Without the demand, there is no poaching and no illicit trade. Well, this is certainly a taut and well-filmed atmospheric piece.

• When Lambs Become Lions is released in the UK on 14 February.