Ideally, I would like a dark, mysterious, urban cover. There is a scene in a low-density forest where the main character Frederich is being hunted by a sociopath while armed with a Glock pistol (I have attached a very rough mockup of this scene).
There is another important scene which begins with Frederich standing in the middle of a street in torrential rain. That is another option, and a powerful scene in the book.
Frederich is in his mid-twenties, with a mop of blonde hair and soft features. Not sure how easy it is to portray this with the available stock imagery. I leave that to you.
You can also go for a more abstract figure. Same goes for the scene.
In regards to font and style. The only preference I have is that the font is thick and spaced out. Otherwise, you can select a generic crime font type and overall style. I'm not looking to reinvent the wheel, just to portray that:
1. It is a crime novel
2. The protagonist is young, Caucasian and an assassin
3. The book is heavily focused on death, political power and murder.
There is also a secondary female character, and you are free to include her if you think it will help. She is in her mid-twenties and has a Spanish appearance.