The penultimate film from Luciano Ercoli, Killer Cop is a sharp and surprisingly nuanced poliziottesco film, balancing pulpy thrills with pointed political commentary. Tellingly, its original Italian title – The Police's Hands Are Tied – is much more fitting than its blander English name. That title doesn't just suggest frustration within the justice system; it captures the film's subversive tone perfectly, hinting at a film where authority is compromised from within.

Detective Inspector Rolandi (Claudio Cassinelli) happens to be at a hotel when a bomb explodes during an international conference, killing several delegates. Due to the political sensitivity of the attack, hardline senior officer Armando Di Federico (Arthur Kennedy) is brought in to oversee the case, gradually exposing a far-reaching conspiracy involving high-ranking officials – possibly even within the police force itself.

Aside from a couple of stylistic flourishes, there's a grounded realism to the film, with a narrative more reminiscent of The French Connection than the non-stop action that typifies the poliziottesco genre. While essentially a standard procedural thriller, there is a clarity to the plot, and a lived-in quality to the performances that elevates the film.

Much of this is due to Claudio Cassinelli's quietly charismatic lead performance. With his dishevelled, long hair and laconic demeanour, Rolandi is a refreshing break from the typical authoritarian, hyper-masculine leads of the genre. Cassinelli initially plays him as laid-back, but his performance gradually intensifies as the stakes rise, building to an explosive final confrontation. There's a neat running gag with his alarm clock that marks him as an unconventional cop right from the start, which is cleverly flipped later to signify his growing maturity.

There's a gentle, almost innocent sense of humour in the film's first half, especially in Rolandi's relationship with his hapless partner (Franco Fabrizi). Fabrizi's warm persona and his character's tendency to crumple whenever he has a gun pointed at him (“You always fall for it!”) make him immensely sympathetic, and their camaraderie brings real emotional weight to the investigation. Elsewhere, Arthur Kennedy joins the ranks of Hollywood actors who carved out second careers in Italian thrillers, playing a straitlaced commissioner with hidden depths; Sara Sperati gives an enigmatic turn as Rolandi's informant and love interest, while Bruno Zanin is strangely vulnerable as the bomber himself.

This is one of the film's more compelling, pervasive ideas: Ercoli presents the anarchists as essentially pawns in a game being played by the shadowy establishment, and they end up more sympathetic than many of the law enforcement representatives, who are largely shown to be either fallible or corrupt.

It's not a perfect film by any means; there are definite pacing issues in the middle, where there is a lot of intrigue and very little action. Also, the action sequences are a very mixed bag – the inciting explosion (inspired by the 1969 Piazza Fontana bombing) is awkwardly staged and lacks impact, with some very ropey effects. Thankfully though, Ercoli compensates for this with some thrilling assassination set-pieces, with the umbrella gun a particularly memorable detail. Similarly, the climactic foot chase – clearly inspired by The French Connection – is filmed with a gritty, near-documentary realism, culminating in an exhilarating shootout on the subway. Oh, and Stelvio Cipriani's memorable, synth-driven score is just incredible, alternating deftly between poppy and operatic.

It may not be a masterpiece, but Killer Cop is a much more thoughtful, stylish, and nuanced film than it needed to be (and much better than that title would suggest). It delivers just enough thrills to satisfy genre fans, while the political undertones, along with Cassinelli's intelligent performance, gives it a vitality that ensures it remains engaging and watchable today.

Blu-ray Special Features

• High-Definition digital transfer, presented with both original Italian and English audio
• Audio commentary with Eugenio Ercolani and Troy Howarth
• Interviews with Valeria D'Obici and production manager Alessandro Calosci
• Reversible sleeve featuring artwork based on original posters
• New English subtitle translation, and English SDH subtitles for English audio
• Limited edition booklet with new writing by Barry Forshaw
• Limited edition of 3000 copies, presented in full-height Scanavo packaging

Killer Cop is released on April 28th