How can you prove that a gun was pressed up against someones head when the trigger was pulled?

To prove that a gun was pressed against someone's head when the trigger was pulled, forensic evidence can be gathered, such as gunshot residue patterns and examination of the wound. Close-range shots often leave distinct marks, like stippling or burns, around the entry wound. Additionally, eyewitness accounts, surveillance footage, or the position of the victim and gun can support the claim. Ballistics analysis may also help establish the shooting distance based on the characteristics of the bullet and the scene.