Felix's research focuses on an adolescent who committed a mass murder at his school. Felix uses data from the adolescent's school and medical records and interviews the adolescent's friends, family, and teachers. Which type of research is Felix engaged in?

Then Felix conducts mixed research method.

Explanation:

Mixed research is a type of research which involves, the use of both non-numerical, non-quantifiable and numerical, quantifiable data to make conclusions. In the above example, Felix uses both numeric and non-numeric data that he collects to make inferences. The medical records are examples of numerical quantifiable data while the message from the interviews is non-quantifiable data.