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Taking the fingerprints of the movers would not be helpful because they packed all of the items originally. It is expected that their fingerprints would be present on all of the items.
I dont believe that hiring a private investigator would help either. Unless your friend has insurance for her personal property, there appears to be little recourse. The police are probably not being helpful because there is really no way to prove that they stole the items.
She filed a police report, but they aren't very interested. Oh well thanks for your time.