Why not do so by passing an order down the chain of command rather than tipping her off by tweeting to the general public?
@Oceander I can think of a couple of reasons,starting with the FACT that we aren't a police state YET,and no President has that authority.
Secondly,it is a old hunter tactic to "shake the bush to see what runs out". She may well panic and make a strategic mistake that could help lead to criminal charges being filed.
I just hope that her passport has already been seized.