LOCATION: (Fresno, Santa Ana)

I separated from my ex 9 months ago. I moved back to Fresno California with our child. He claims (in court) to have recently moved back to Fresno from Santa Ana solely for our child in order to get more visitation. Ive full custody and a restrainting order against him. He gets every other weekend in visitation. However, he claims to be umemployed (attempts loopholes to child support) since he quit as a mechanic for an Audi dealership in santa ana (makes over 100k when i did live with him ). Yet, i called Audi in santa ana and they claim he still works there. How do i prove that he is still employed and has a sizable income? Please advise thank you