Any dramas where the MC helps the police solve crimes despite not actually working for the police?

I just binged the j-drama "Don't Call it Mystery" and was vividly reminded of how much I love shows like these ... does anyone have any recommendations? Country of origin, length, etc, doesn't matter so long as the main character gets to solve crimes and help out the police despite them not actually being a cop. Thank you so much! <3

• The Killer's Shopping List 
• Be Reborn 
• Inspector Koo - FL is a PI for an insurance company but ends up solving murder cases