he was picked out in a lineup you moron.
Police have been known to rig line ups. One guy was dressed by the police exactly like the suspects description (they provided the clothes as they hadn't found anything similar when searching his apartment) and didn't dress any of the other people in the line up that way. He was eventually exonerated. Police have been known to rig things when they are SURE of guilt but don't have the evidence, this is just one example.
Fingerprint evidence can be as bad. You may remember after the Madrid bombings the FBI was asked for help with the fingerprints. They found about a dozen people who were partial matches to the fuzzy digital photo of the prints. They chose the Moslem and assumed his guilt with no evidence he was out of the U.S., they pointed to one of his child custody clients (he was a lawyer) was found to have "terrorist connections" (and that may be that someone you casually know casually knows someone related to a suspected terrorist they never met) AFTER he was no longer a client. When the Spanish authorities said it can't be him, here is a clearer image of the prints they refused even to check. He was held SECRETLY in custody with the police denying it (Patriot Act) for some time with no contact with family or a criminal lawyer). The Spanish caught the real criminal.
Another way police misuse fingerprints is that if they KNOW they have the right guy but the fingerprint expert says "not a match" they keep resubmitting it and insisting on another review till the expert says "OK, you're right, just leave me alone" just to get them of HIS back. The expert of course should be reporting them to their higher ups for trying to coerce a false experts report.