I googled "John Smith", he looks just as the Perugia police "should" imagine Mr. Smith:
http://www.d.umn.edu/cla/faculty/troufs/Buffalo/images/pf025534.jpg
That's an unfair comparison. I think that if, for example, in London, Paris, Oslo or Perugia, you asked 100 people who had at least a smattering of world views (let's say for example, 100 people who were educated to "graduating high-school" standard - or "A" level standard in the UK equivalent) what the ethnic origin of an adult man with the surname "Lumumba" was, I think that over 90 would say that he was of African origin. The name has no roots or similar examples anywhere in European etymology.
Those who had a more sophisticated knowledge of world politics and history might of course remember that Patrick's very-near-namesake, Patrice Lumumba, was the first Prime Minister of the Republic of Congo, who was assassinated in 1961 in a dirty little murder that possibly involved the CIA and Belgian intelligence. Indeed, I think I'm right in saying that Patrick Lumumba claimed at some point to be a relative of Patrice Lumumba.
Incidentally, my "100 person" argument above specifically mentioned a MAN named Lumumba. This qualifier is important, since it would be far less logical (and in fact possibly even indicative of some form of racial bias) to assume that a WOMAN called Lumumba was of African ethnic origin. This is, of course, because it's perfectly likely for a Caucasian, Asian, Hispanic, American Indian (etc) woman to marry a man of African origin, and to take his name.
The only other point mitigating against a rational racial identification from that name is if the person in question was the descendant of an unbroken paternal line of Lumumbas, all of whom had borne children with non-African women. In other words, the Lumumba in question might have had a father of African ethnicity named Lumumba, and a white (for the sake of argument) mother, and would therefore have been of mixed race while preserving the Lumumba surname. Or, in a more extreme example, the Lumumba in question might have preserved his name via his great-grandfather on his grandfather's and father's side, but all the females in this area of the family tree had been white. If this were the case, our Lumumba would be only 1/8 African by ethnicity, and 7/8 Caucasian.
But the above examples, I'd argue, would carry less weight in Italy. Only 0.44% of the Italian population were immigrants from sub-Saharan Africa as of the Jan 2009 census. And most of these were first-generation immigrants. So there had not yet been much of an opportunity for males of African origin to couple with Caucasian or other ethnic origin) women, and to have mixed-race children who'd grown to become adults. Although, interestingly (but irrelevantly to this argument), Patrick himself had married a Caucasian women, and together they'd had a mixed-race child who presumably bore the surname Lumumba. The key word here, of course, is "child".
Sorry to go to the "n"th degree here! But, in the current climate, I'm trying to close off all the "AHHHH! But you missed this! What if...?" responses. So I'm probably saving myself (and the forum) time in the long run...........