Nice work finding the "receipt stamp". I've always wondered about that. I'd assumed that Repubblica had gotten its copies of the Niger docs from Panorama. But the fact that the receipt stamp was covered up suggests their source was someone else.
After reading your post, I checked if there were any other differences between Panorama's Doc 4 and Repubblica's Doc 4. There appears to be a "telltale splotch", I guess you could call it, on Panorama's Doc 4. It's a third of the way down the page on the right-hand margin. In fact, the same mark appears in the same position on all of Panorama's Niger docs but on none of Repubblica's. Like the receipt stamp, the telltale splotch seems to have been removed from Repubblica's copies.
Could you post the rest of the Panorama versions of the Niger docs that aren't already online? I'd like to see if there are any other differences with Repubblica.
Thanks. :)
The blob on the right on all of the documents in Panorama appears to be a stamped signature. Where it is clear it seems to read "A Bulba" but is most likely "A Burba" as in "for/to Burba" or "E Burba" which stands for Elisabeta Burba.
It either means it's her property or story inside the Panorama office, so she, or someone else, stamped it with an ID.
I can't come up with another explanation, but I don't think it's too important.
According to her account and the Martino secret tapes, she received the docs outside her office. Presumably she kept a lid on the story in the office.