Does DCFS/CPS keep juvenile case files? (Possible trigger warning)

Super random question for this app but... in case anyone knows, I have tried to request for disclosure of juvenile case files regarding a sexual abuse investigation from when I was a child in 2002. After several calls and filling out and sending the JV-570 form I was told DCFS LA County could not find any juvenile record of me. I was told by my parent that I had received psychiatric evaluations as well as supervised visitations with my father who was the one under investigation. I’m not sure if it went any further than that. Do they hold onto every case file, even investigations that were dropped? Would they keep documentation of what I had gone through as a child? Any help would be so appreciated as I can’t seem to find any answers from them and it’s so frustrating.