India, July 22 -- A woman gets bail because the police, arresting her for her husband's murder, never told her why she was being arrested. A former chief minister walks free because a charge-sheet dissolves into inference stacked on inference. A clinic in Hisar gets acquitted 19 years after a raid because the complaint against it bore one signature where the statute demanded three. Three courts, decades apart, arrive at the same finding: The police investigative process is broken.

The Code of Criminal Procedure of 1861, and its 1898 successor, were built by a colonial administration that wanted order rather than rights. Independence changed the purpose of the policework. Articles 21 and 22 arrived as a new demand laid over an old machine...