Because this specific string is quite niche, it could mean a few different things:
It looks like you’re referencing a specific file name——which often appears in the context of internet mysteries, ARGs (Alternate Reality Games), or "lost media" creepypasta stories. BL - alex.harper.mp4
While it is most likely a reference to a story, could you clarify what you're looking for? Are you trying to find the source of this video, or Because this specific string is quite niche, it
It might be a fictional "cursed" or "found footage" file name used in a digital horror story or an Unfiction project. ARGs (Alternate Reality Games)
You could be asking me to write or "feature" a story based on this specific file name.