One can always phrase things in a positive or negative way. I don't condone the FBI's behavior but I've noticed that law enforcement agencies tend to operate a bit like computer programs in that they get a lead, they follow it until they can either say "relevant" or "not relevant" and in this case they had a lead from their lab which was unresolved. So they kept pushing on it.
Forensics, as most people should know, isn't an "exact" science, its a statistical science. It is entirely credible that Mayfield's fingerprint in their database was the closest match in the database for someone who was known to be in the area. It reads like it wasn't all that close a match as the Spanish authorities had discounted it, but from the FBI's process perspective it was a "lead" to run down.
The article says that the FBI didn't follow their _own procedures_ for matching prints. But procedures be dammed because the guy had an arrest record, which was also erroneous, and a Egyptian wife. It doesn't matter how exact or inexact the science is if you aren't even going to follow your own established procedures. The irony of your argument is that they would have reached the correct conclusion if they had in fact operated like a program.
"Despite finding that Mayfield’s print was not an identical match to the print left on the bag of detonators, FBI fingerprint examiners rationalized away the differences, according to a report by the Department of Justice’s Office of the Inspector General (OIG)."
It seems they need to totally separate the finger print examiner from the investigating officers so that they can't be influenced by outside circumstantial facts.
You read the article right? Al Jazeera implies they didn't follow their own procedures, not the FBI. The FBI constructed a theory, and sought to validate or invalidate it.
You can read the actual OIG Report [1] it is online, but the interesting bit is here, in Chapter 7 (page 269):
"Based on our investigation, we concluded that the three FBI examiners who misidentified Mayfield's print were confused by the fact that the fingerprint on the Madrid bag contained as many as 10 points that corresponded to details in Mayfield's known finterprints in relative location, orientation, and intervening ridge count. This degree of similarity is extraordinarily rare and confused three FBI fingerprint examiners as well as a fourth, outside, court appointed examiner."
I don't know how much you know about fingerprint forensics, I just know what I read, but a 10 point match is considered pretty strong from what I've read. And as I mentioned earlier, its a statistical thing not an exact thing.
Al Jazeera isn't implying it they are stating facts directly from the FBI OIG's own report. Check out Chapter 4 page 128 it says that one of the examiners didn't follow proper procedure, there was intense pressure because of the magnitude of the case and the two others who reviewed the initial finding had knowledge of the initial conclusion so there was pressure on them to agree with it.
Forensics, as most people should know, isn't an "exact" science, its a statistical science. It is entirely credible that Mayfield's fingerprint in their database was the closest match in the database for someone who was known to be in the area. It reads like it wasn't all that close a match as the Spanish authorities had discounted it, but from the FBI's process perspective it was a "lead" to run down.