Ok let me put on my tinfoil hat for a moment.
I think the theories on why it took so long for this image to come out are probably true. A former Fred Meyer Gas employee makes a lot of sense if we examine where exactly this picture was taken from:
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The picture was taken facing the last 3 lanes of the gas station (looking south). Dave was parked on the wrong side, the gas pump was on his right. If we use the white arrows on the ground as reference you can see the layout in the next picture.
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Because you cannot clearly see the bottom of the first arrow here, this picture must have been taking from the south side of the attendant room, not from across the parking lot. Now lets see what this room looks like from the other side.
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DSP was parked in the 2nd spot. Notice the initial picture has a downward angle, allowing the camera to capture an divot in the pavement (circled in blue in this picture). The camera man must have been standing just a few feet from this corner, which either places him/her inside or just in front of the attendant's building.
In summary, this was likely a gas attendant who was standing in the doorway to the building and noticed DSP.
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The door to the building lines up exactly with the divot in the pavement.
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