Just to touch on the role of a criminal defence lawyer, which I have never been, when I was in school one of the professors described it as the lawyer was protecting the entire system by ensuring that only those that can be proven to be guilty are found guilty. This means vigorously challenging the evidence of witnesses and ensuring that the police follow the proper protocols in gathering evidence.
That struck a chord with me as a lot of the actions of accused are pretty heinous but they still deserve a strong defence as it ensures the system continues to work as well as it can, not to say it is perfect by any means.
"It is better that ten guilty persons escape than that one innocent suffer",
...as expressed by the English jurist William Blackstone in his seminal work, Commentaries on the Laws of England, published in the 1760s.
https://en.wikipedia.org/wiki/Blacks...7s_formulation.