This is an astonishing distortion of what actually happened! The police and prosecutors mistreated Lumumba and told him that he'd made an appointment with AK to go to the cottage to have sex with MK. His remand hearing declared that he'd had violent sexual activity with MK. The police publicly congratulated themselves on solving the case: Lumumba did the dirty deed while AK stood back and covered her ears.
The way in which the alibi-creating Swiss professor was found is utterly at odds with your fallacy that the police "went out of their way" to track him down. In fact, Lumumba himself pleaded repeatedly that a Swiss professor (whose name he couldn't remember) was there at the bar that night and could provide him with an alibi. This information got out to the media, and an Italian friend of the professor's saw it on TV. The friend then phoned the professor in Zurich to tell him that he might be of some importance in the case. The professor Googled the Perugia police number and phoned them, only to be told that he'd have to call back the following day when the relevant detectives were around. Instead, he called back the same day to tell them that he was coming to Perugia of his own volition - which he did.
So to say that Lumumba's alibi establishment was the result of dogged and "over and above" police work is arrant nonsense. If anything, the police tried to obfuscate and delay in this regard, but one can at best take the line that they certainly weren't "going out of their way".
And that such a self-professed student of the case can make such a clearly incorrect and misleading assertion is simply breathtaking. As is the blithe assertion that police arrest and release people after a few days all the time. Astonishing, simply astonishing, and indicative of a certain mindset I think (for balance, and to mitigate against a knee-jerk "FOA" name-calling, I'm also opposed to some of the more extreme opinions expressed by posters holding diametrically opposing views to that of the eminent Mr Fulcanelli).
PS: I'm assuming that you can actually determine the satire/sarcasm in the original phrase "who cares about African immigrants anyway", but that you then still choose to twist that phrase round to rather nastily imply a degree of casual racism on behalf of the author (who I'm not a flag-waver for on the whole, by the way). Or maybe you really don't spot the satire/sarcasm?