I hate it when people sacrifice clarity for the sake of brevity. It would have been much clearer with the change of a single word:
Those probationary officers -- called PPOs in cop parlance -- have been fired by police Supt. Phil Cline.
The writer could have added the largely irrelevant fact that they are female as a side descriptor, a la:
Those probationary officers -- called PPOs in cop parlance -- have been fired by police Supt. Phil Cline. Both PPOs are women, while the third fleeing officer is male.