What happens when an arsenal of military style weapons are given to a police unit? Peace Officer is a documentary investigation of this increasing militarisation and subsequent mistrust of American SWAT forces, and an incredibly timely and bone-chilling piece of cinema that investigates the very notion “to protect and serve”.

The story begins with police footage of a 2008 residential SWAT team operation in Utah which quickly turns fatal, as witnessed by the film’s main character “Dub” Lawrence. He’s an all-American, salt of the earth man with one of the most heart-warming smiles you’ll ever see. Dub reveals his own investigation of the SWAT operation has consumed his life ever since, as we discover the man killed in the raid was in fact his son-in-law.

The strength of this documentary is the unique perspective offered by Dub, who was once upon a time a sheriff, and known as the most honest officer in the force after issuing himself with a ticket for a parking infringement. In 1975 he established one of the first SWAT units in Utah, but has now found his family victim to the trigger-happy police unit. Dub’s thorough inside knowledge of the unit is used to reconstruct three different SWAT operations, which he likens to having a video camera recording every moment at the scene, revealing official reports are not as they seem.

Peace Officer’s perspective also allows the film’s directors Scott Christopherson and Brad Barber wide-ranging access to both sides of the militarisation argument. The film features interviews with members of another SWAT unit, interviews with a family who experienced a mistake raid on their home based on incorrect information, and perhaps the most bone chilling scene, an interview with the family of a man killed in a SWAT raid who visit the scene of their son’s death.

Like Making a Murderer, Serial and other recent true crime accounts, the filmmakers also make use of copious amounts of police evidence in the form of photographs, video footage and audio available under the Freedom of Information Act.

Peace Officer is completely deserving of the Documentary Grand Jury Award it received at the 2015 South by Southwest Film Festival, and a poignant warning to us all about the changing face of forces employed to protect us.