yes you do need to know math to be a private investigator. cause being a private investigator you have to have the skills of computers and a ton of things. Added later: You need to be able to...
I'm not sure that they do use that much maths.
Yes.
No more than the average person. They don't need math for the job though.
Mathematics were tossed out around the same time Ethics were in the criminal justice system ... hence, Court System.
How an Investigator Became a Math Teacher
The Psychology of a Criminal
The Role of Psychology in Criminal Interrogations
No Criminal Charges for AIG