What the motion does
Defense counsel can send a preservation letter to a business, a police agency, or another holder of records, asking them not to destroy material. When that is not enough, or when the material is in the government's hands, counsel can ask the court for an order directing that it be preserved. Courts generally expect the prosecution to keep relevant material it has, and the loss of evidence can lead to remedies such as an instruction to the jury, depending on the circumstances. Private businesses such as stores or apartment buildings may have no reason to hold on to video unless they receive a request or a subpoena.
Timing and targets
Store and building cameras often record over themselves within a short period, and phone carriers keep certain records only for limited times. Identify each possible source quickly, including camera locations, the 911 call, police radio traffic, and any rideshare or app data. Do not try to collect video yourself by returning to a scene or contacting witnesses, especially if an order of protection is in place. Give your lawyer a list of places and times so that requests can go out promptly and a subpoena or motion can follow where needed.
In civil cases too
Preservation matters outside criminal court as well. In civil litigation, a party that reasonably anticipates a lawsuit generally has to preserve relevant evidence, and courts can impose sanctions when evidence is lost or destroyed. The same video or phone record may matter to both a criminal case and a later injury claim, so early requests can serve both. In a first meeting we identify what evidence exists, who holds it, and whether a letter, a subpoena, or a court motion is the right tool for each item.
