employee embezzlement

Im dentist. Had employee of six years embezzle me. Evidence was gathered by expert on our dental management software and by a Forensic accountant. Both agree, evidence is sufficient to prosecute. Case handed over to Police detective experienced in embezzlement cases. He initially investigated case and felt we had a case. But now he never updates us. Never returns phone calls. This has gone on for months. don't know what I can do to pursue this case.