A case can fall apart fast when nobody can show who handled a key piece of evidence, where it was stored, or whether it was changed along the way. Chain of custody is the documented trail showing possession, transfer, storage, and handling of evidence from the moment it is collected until it is presented in court. That record helps prove the item is the same one involved in the incident and that it was not altered, contaminated, lost, or mixed up.

In practical terms, this matters most with evidence that can be questioned easily: damaged vehicle parts after a crash, blood samples, medication bottles, surveillance footage, torn safety gear, or a phone containing photos and messages. Each handoff should be logged, with dates, names, and storage details. If there are gaps, the other side may argue the evidence is unreliable or should be excluded.

For an injury claim, a broken chain of custody can weaken proof of causation, damages, or even fault. That can matter in Massachusetts auto cases, where PIP benefits are required under the state's no-fault system and stronger evidence may become crucial if injuries are serious enough to move beyond basic insurance claims into a lawsuit. After a pothole crash, a work injury, or a long backup collision near the Sagamore Bridge, preserving evidence immediately can make the difference between a solid claim and a preventable loss.