A 31-year-old off-duty Brooklyn cop is in custody after confessing to shooting her own girlfriend after finding her in bed with another woman. Assistant Chief Michael Kemper says it all happened just after 5 p.m. Wednesday. The officer's 23-year-old girlfriend was taken to a hospital for treatment of a non-life-threatening injury. The 25-year-old other woman, however, died from her injuries. It's believed that the off-duty officer was inside the home before the two women arrived.