Atlanta's police chief has announced sweeping changes to his department, including the replacement of the entire narcotics unit.

The unit came under heavy criticism last fall after the shooting death of 92-year-old Kathryn Johnston during a drug raid. Officers burst into her home unannounced, with a no-knock warrant based on false information. Two of the officers involved have pleaded guilty to manslaughter and other charges, while a third is still facing prosecution.

Police Chief Richard Pennington says training standards for the narcotics unit will be rewritten to adopt federal drug agency practices. He says 14 investigators will be added this month, and he hopes to have a new staff of 30 by the end of the year.

In all, Pennington announced more than 140 personnel changes, including major changes in the department's leadership. [MORE]