When client budgets are tight, there is a reluctance to spend money on professionals such as forensic accountants and private investigators. But I have learned that the do-it-yourself method (either the client doing it or the attorney doing it) often misses the mark. There is a reason why professionals are trained in specialty fields. Simply put, the professionals have training and techniques that go beyond what an attorney can typically do.
Brian Willingham at Diligentia Group (private investigators) wrote an excellent article on attorneys using private investigators. Among the things a professional private investigator can do for a client are locating assets and doing historical reconstructions (such as piecing together family history to locate heirs).