This comes across as a classical Mafia style hit, except that those doing it today are often state actors, aka assassins.
The shooter is not a typical person. Notice how far she ran to close the gap? Not an easy thing to do when you are full of adrenaline. And lawyering up an turning herself in is also very peculiar.
The clincher will be if the victim turns out to be a political refugee from some African dictatorship that she has worked to overthrow, or is a close relative to an opposition leader.
Not a true pro. It would have been easy to have had a mask on the entire time, and with several blocks thrown in. The gait would be a easy tell, but at least have a mask on to get some time added.