To prove someone slashed your tires, you must have evidence showing that the perpetrator committed the act. This evidence might include security camera footage or eyewitness reports from people who saw the suspect doing the deed. Additionally, any physical proof left behind, such as scrapes or broken pieces of metal, can be collected and used as evidence. Finally, tire marks on the ground or surrounding areas may help to show a trajectory of events leading up to the slashing of your tires.