How can I find out if a deceased relative left a will, and what happened to her property? (Pennsylvania, NY)?

Her holdings were quite substantial, with homes in PA and NY. Death was sudden, in July of 04. No one was notified. A "friend" handled the memorial service and cremation, and would tell us nothing!!!!! We are almost positive there was a will, as it was witnessed by a family member.(He died a few weeks after she did. When we went to notify her of his death, we discovered she wad gone too!!!!! ) Her immediate heir (son) was a minor with special needs, and he has DISAPPEARED, as has the "friend"!! The sweet child has since turned 18, but cannot function mentally or physically unisted. The private school he attended has closed. There is a large some of money involved, and we want to make sure he was not taken advantage of. WE ARE NOT AFTER HER MONEY FOR OURSELVES. Is there any way I can investigate this as a lay person, or must we hire a lawyer or go to the police?