Latent fingerprint analysis is one of the more well-established domains of forensic science, yet these human examiners are vulnerable to the same confirmation biases that plague us all. It logically follows that other, less 'scientific' domains of forensic science that involve visual comparisons could be similarly hampered.
Over the last decade there have been dozens of reported cases where an attorney has dug deep into the case file and found untested DNA that could exonerate their client. But often when they return to court to ask for the right to test the new evidence they are told judges don't have the power to force prosecutors to re-test.