1. Special agent, Forensic Science Research and Training Center, FBI Laboratory, FBI Academy, Quantico, VA 22135, US.
2. Deputy director, chemist, and biological laboratory technician, respectively, Laboratory of Tumor Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, US.
3. Physicist, calibration technician, and physicist, respectively, Ionizing Radiation Division, National Institute of Standards and Technology, Gaithersburg, MD, US.
4. Special agents, Scientific Analysis Section, FBI Laboratory, Washington, DC, US.