Phone records are the case.
We send a preservation letter to the at-fault driver and a subpoena to the carrier (Verizon, AT&T, T-Mobile) within the first 30 days. Cell tower records, SMS/iMessage timestamps, app foreground activity, and even screen-on data — modern phone forensics can prove the driver was distracted at the exact moment of the crash. Without the preservation letter, this data is purged within months.