Spoliation is the legal doctrine that addresses the destruction, alteration, or concealment of evidence by a party who knew or should have known the evidence was relevant to actual or anticipated litigation. Courts have a range of tools to address it, from sanctions to outright adverse-inference jury instructions.
Preservation duties attach earlier than many parties realize. For an injury case, the duty to preserve a vehicle, the dashcam, the surveillance video, the maintenance records, or the cell phone often attaches the moment the incident occurs — and certainly when a preservation letter is sent. Routine destruction policies are not a defense if the policy was applied to evidence the party knew was relevant.
Spoliation letters — sent within days of a serious crash — are one of the cheapest, highest-leverage moves in PI practice. They convert what would otherwise be 'routine destruction' into willful spoliation if the records are not preserved.