In four rape - murder cases - involving female victims who were eight, nine, eleven, and sixty-eight - the DNA from the semen did not match the man charged with the rape and murder.
The prosecutor is pursuing these cases anyway, waving away the DNA evidence and the science upon which it is founded as a "red herring."
Unfortunately, I know it's not really that rare. A DNA exclusion did not prevent Michigan authorities from imprisoning Nathaniel Hatchett for rape. Twelve years is what it took before someone who knows something about DNA refused to accept the prosecutor's flimsy arguments. Shame, shame on the judges who permitted this man to go to prison for rape when the seminal DNA excluded him as the rapist!
I am seeing more and more of these cases - representing more and more prosecutors who won't let a lil' ol' thing like DNA get in the way of a conviction. Alas, some juries are willing to accept this. Indeed these cases are becoming so common I wish someone would coin a term for it. "DNA non-match" cases isn't very catchy.