Did Miller Get Nielsen Fired?

Multiple reports indicate the White House adviser Stephen Miller has orchestrated a hardline shake-up of the DHS.
Business Insider reports that on Sunday, Kirstjen Nielsen announced her resignation as secretary of homeland security.
President Donald Trump was reportedly concerned that Nielsen had not taken tough enough stances.
On Friday, the Washington Post reported that Trump recently told Miller he was in charge of all immigration and border affairs.
Illegal border crossings at an 11-year high in February.
The Trump administration has renewed attempts to crack down on migration from Mexico.