A far future tale of a desperate flight from a merciless foe. Told in epistolary form. Indeed, with an explanation of how the documents were gathered.
Ezra Mason and Kady Grant had just broken up that morning when their planet -- an ice planet with an illegal mining operation -- was attacked. The first documents, after the cover letter, are their interviews after the panicked evacuation, which failed to save many residents. Such as Ezra's father.
Difficulties rapidly mount in a manner that telling much of would be spoilerish. But three ships get away with refugees, pursued by one that evidently wants to destroy the evidence. And that's only the beginning of the tale.
The format is handled well, with the accuracy of style you need so much in a variety of documents.