[Someone]

There's an other issue: one can question the quality of judgment of the paper's editorial office.

Their primary source apparently is not the most reliable, and figuring that out is not hard. They either did not know that, which would be bad, or they knew and ignored it, which would be bad, too. The third option 'they knew, but had a secondary source confirm it' seems highly unlikely as the article doesn't mention it. Also, if they had conformation, why would they have to retract it?

And yes, one can read a conspiracy theory behind the phrase "Madsen, who has been attacked for holding controversial views on espionage issues". I don't think that is enough for a respected paper to justify publication of this article.

[Amadou]

That third option could be that they had a second source confirming things while the article was in process but that source was ruled out (either reversed themselves or was found to be making stuff up) and the editors made a bad last minute call to continue but then were overruled a few minutes after initial publication.