Yes, he definitely should be charged with murder or manslaughter. Letting him walk away without charging him with a crime would be such an insult to the woman he shot in the face and a travesty of justice. She is an American citizen and she was unarmed. Reports indicate that she sustained multiple gunshot wounds to her head and face.

I watched the video, and she didn't look like she was a threat to him. She was trying to drive away from him with the wheels turned right away from the agent, and he shot her from the front side of the car at close range.

This is the video.

https://www.youtube.com/watch?v=CQCvNExBDjE

Kristie Noem, Trump's pick for DHS, ICE, is an incompetent idiot who hired a gang of unqualified bullies, thugs and misfits. She had ZERO experience in law enforcement prior to becoming Secretary of Homeland Security.

She was a huge Trump supporter and popular in the Republican Party (anti-abortion, denies climate change, very conservative, etc). That is good enough for Trump. Qualifications don't mean diddly squat. With Trump it's totally about loyalty to him and his political agenda.

https://en.wikipedia.org/wiki/Kristi_Noem