O.J. Simpson's Ex-GF -- Arrested for Purse Snatching

1:25 PM PT -- Prody just pled "not guilty." She's currently being held on $10,000 bail.

O.J. Simpson's ex-lover -- the one he didn't kill -- was arrested in Fargo, North Dakota this weekend ... after cops say she snatched a purse from a woman outside of a mall.

According to police, Christie Prody -- who dated Simpson from 1996 'til 2009 -- didn't get away with the purse ... 'cause the intended target fought back ... and struggled with Prody until mall security arrived.

Cops told KFGO ... the victim suffered minor injuries in the incident.

It's been a rough year for Prody -- back in April, she was charged for stealing pain killers from a home where she worked as a nurse's aid.

She was also shopping a sex tape back in August, but we don't know if she ever found a buyer.