The central mystery of "Loving Vincent" is never definitively solved, which is itself the film's ultimate point. Armand's investigation into whether Vincent's death was suicide or murder leads him to a series of contradictory conclusions. He initially suspects Dr. Gachet, who argued with Vincent shortly before his death and who seemed jealous of his talent. Later, strong evidence points to René Secrétan, a local teenager who owned a gun and habitually tormented the artist. Dr. Mazery, who examined the body, opines that the angle of the shot and the lack of powder burns make suicide unlikely.
The climax of Armand's investigation comes in his final conversations with Marguerite and Dr. Gachet. Marguerite confesses her close friendship with Vincent but doesn't believe René was capable of murder. Dr. Gachet finally provides his own theory: that his heated accusation that Vincent was a burden on his brother Theo is what drove the artist to kill himself to set Theo free. However, the film leaves this as just one more interpretation. The final reveal is not a 'whodunit' but a profound emotional understanding. Armand concludes that it doesn't matter how Vincent died; what matters is the life he lived and the beauty he created. The true 'spoiler' is that Vincent's death was likely a tragic, complicated event, and he may have claimed it was suicide to protect the young man who might have accidentally shot him, a final act of pained empathy. The film concludes with Armand receiving a letter from Theo's widow, which includes one of Vincent's own letters, signed "Your loving Vincent," bringing the emotional journey full circle and emphasizing the love and connection that persisted through the tragedy.