Twins DON'T have identical fingerprints. Fingerprints are a result of genetics. 
 "What showed up in twins' fingerprints, the basic skin patterns of loops and whorls and ridges, was identical, the product of shared genes." p.142 
 I'm surprised the author could get that by his agent and editors. The whole premise of not knowing which twin left the fingerprints at the crime scene (and therefore maybe the wrong twin went to jail) is just wrong. The half of the novel is slow; the plot twist and conclusion is too far-fetched.