Can I find a lawyer in my son’s case?

My son was killed last year and the case is still under investigation. So the police took his iPhone out of my house when it was never on the scene. After that, they informed me they’re going to open the phone to see if there’s some details on the investigation I’ve been asking for, and they’re offering it to me, and it’s never been activated. I called the Apple store to unlock the phone because I was my mom, but they said I needed permission from the court. I have documents, but I can’t find who can file them. Another issue if I found any details on the phone that I might prosecute because the police department was lying to me saying they unlocked the phone and I can see that the phone was never unlocked. Can you help me?