Women are the fastest growing population in the criminal justice system. Low level drugs offences and crimes associated with poverty have swept in hundreds of thousands of women across the US.

It's like a maze with a bunch of mice in it that are fed poison.

Sonja Marcus, a former prison inmate

Many have spent years behind bars for non-violent offences.

In California, after promises of prison reform, women continue to face some of the highest levels of overcrowding.

And while the state boasts of significantly reducing the female prison population, county jails have disproportionately filled up with women who are still being swept in for the lowest-level crimes.

Allen Hooper, from the American Civil Liberties Union, explains: "The prison construction, sort of filled a void and a vacuum, both in terms of keeping the economy going just with the construction and the jobs and then also people who were unemployed because of the economy who get caught up in crimes of poverty ... You scoop them up you figure out excuses to put them in those cages."

Fault Lines travels to California to look inside the criminal justice system and asks why so many women are behind bars. 

Fault Lines can be seen on Al Jazeera English each week at the following times GMT: Wednesday: 2230; Thursday: 0930; Friday: 0330; Saturday: 1630.

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