Nearly 20 years ago, Nick Broomfield released his sensational documentary Biggie and Tupac, in which he uncovered hidden facts about the violent deaths of US rappers Tupac Shakur and Christopher “Biggie” Wallace, and found that intimate witnesses to this murderous bicoastal feud were willing to open up to a diffident, soft-spoken Englishman in ways they never would to an American interviewer. Since then, there have been two very unedifying movies about Tupac: the sugary docu-hagiography Tupac: Resurrection (2003), produced by the late rapper’s mother, and the similarly reverential drama All Eyez on Me (2017).

Now Broomfield returns to the same subject, updating his bleak picture of the 90s rap scene, a world in which energy, creativity and radical anger were swamped with macho misogyny, drug-fuelled gangbanger paranoia and a poisonous obsession with respect. Marion “Suge” Knight, head of Death Row Records in Los Angeles, cultivated a violent gang-cult image by associating with the Bloods, and encouraged his acts and proteges to do the same, including Tupac – and Biggie’s perceived oppositional identity condemned him. But even more disturbingly, the LAPD allowed its officers to moonlight at Knight’s firm as “security” (a term that euphemistically covers all manner of paramilitary violence and intimidation).

LAPD officers, greenlit by Knight, were almost certainly involved in the Biggie murder that followed the Shakur shooting. The case is a symptom of police corruption, but perhaps quite as disquietingly, and subtly, this documentary challenges our placid assumption that the media-creative industries must always be respectable in their glamorous artistic prestige, however much individuals may fall short. Here it seems that Death Row Records was simply a criminal organisation, of which rap music was a byproduct. The talent it somehow nurtured in this way looks even more tragically fragile.

• Last Man Standing: Suge Knight and the Murders of Biggie and Tupac is screening on 30 June with a recorded Q&A with Nick Broomfield, and then on general release on 2 July in cinemas.