As an alternative I'd like to offer that perhaps Lumumba did tell The Mail what they did report. I can imagine that the 70.000 Euro they offered for the interview could have been a good incentive to spice things up a little. If Mignini has proof that the claims that were printed are bogus, and the Mail has proof that Lumumba did say those things... then Lumumba is stuck.
Thus the subequent public statements by Lumumba that he didn't make those claims in The Mail... that removes the threat of a slander suit by Mignini. And I doubt that The Mail would be interested in pursuing the matter unless they can earn money with it.
I'd agree that this is a feasible scenario. However, you can't play the game that Lumumba would have had to have played in order for this scenario to work.
To take my David Beckham example again: suppose that the Mail was looking for a bit of spice, and persuaded me to say (dangling a few extra carrots in front of me) that Beckham punched me in the face during dinner (when this had not in fact happened). After the story appeared in the paper, and after David Beckham's lawyer had given me a friendly phone call, I might go on television to announce that I hadn't in fact said these things. "Sorry David", I might say to camera, "I didn't tell the Mail that you punched me in the face, and in fact you
didn't punch me in the face. Hope that makes everything OK".
But it wouldn't make everything OK. For a start, I could accuse the Mail all I liked of making up quotes from me, but if the Mail didn't apologise and retract unilaterally, then the public (and the media) would be entitled to believe that I was lying in accusing the Mail of making up the quote - unless and until I successfully challenged it in a court of law. "Publish and be damned" and all that.
Secondly, and more importantly in this scenario, there would still be the issue of the Mail accusing David Beckham of punching me - via my quoted accusation. It's not a defence for a newspaper to claim that they were merely quoting a third party. So, in this instance, David Beckham's lawyers would be onto the Mail in a shot to demand a retraction and apology for printing the quote - with all that it implied about Beckham's character. If the Mail refused, I would be fairly confident in predicting swift legal action.
Has the Mail ever printed a full retraction of the original story? The retraction would look something like this: "We would like to state that Mr Lumumba now says that he never made these accusations against the Perugia police (or "Mr Lumumba now says that he was incorrect in his accusations against the Perugia police"), and that the original article should therefore in no way imply that the Perugia police ever engaged in any malpractices towards Mr Lumumba."
I might be wrong, but I don't think that such a retraction has ever been offered by the Mail. So why isn't the Perugia police force suing the Mail? At this point, it's important to note that
not only would Lumumba have had to retract his accusations: the Mail itself would
also have had to print a retraction based on Lumumba's retraction in order to immunise itself against legal action from the police.