According to a LA Times report about one county jail:
Hundreds of people have been wrongly imprisoned inside the Los Angeles County Sheriff’s Department jails in recent years, with some spending weeks behind bars before authorities realized those arrested were mistaken for wanted criminals, a Times investigation has found.
The wrongful incarcerations occurred more than 1,480 times in the last five years. They were the result of a variety of factors, including officials’ overlooking fingerprint evidence and working off incomplete records. . .
The number of mistaken identifications per year has been declining, but the department is still on pace to record nearly 200 wrongful detentions this year. For those who are jailed, the experience can be harrowing.