Johannes Mehserle walks out of prison one year . The former Oscar Grant 's officer was convicted of involuntary manslaughter in BART death . Johannes Mehserle served two-year of a two-year sentence because of credit for good conduct .
Johannes Mehserle walks out of prison early Monday . The former BART officer was convicted of involuntary manslaughter in Oscar Grant 's death . Mehserle served one year of a two-year sentence because of credit for good conduct .