Are you writing about the file, or using the file as evidence in a report?
Identify the specific company or organizational rule that was broken [1.1.1].
To provide a more accurate write-up, please clarify the following:
State the facts clearly—what happened, when it occurred, and where "9891mp4" fits into the context (e.g., "On [Date], the file 9891.mp4 was found to be in violation of policy X").