Cleanskin
(2012)

Ewan (Sean Bean), is working as a secret service agent tasked with finding and stopping a terrorist named Ash (Abhin Galeya), who plans to use bombings to make people pay attention to his cause. However, Ewan is actually being used and manipulated by his partner and his boss/handler Charlotte McQueen (Charlotte Rampling) to further political careers and influence voters for an upcoming election by using terror.

Ewan's partner tries to kill him, seemingly ordered to do so, but Ewan kills him instead.

Ewan discovers the conspiracy and finds proof, but knowing he won't be believed with the proof alone, he confronts his boss (Charlotte) at a remote park bench at her home, and then slits her wrists leaving her to bleed to death with a suicide note confessing the conspiracy and her crimes.

Thanks Melissa S!