Thereafter, Mullis worked intermittently as a consultant for multiple corporations and institutions on nucleic acid chemistry and as an expert witness specializing in DNA profiling. While writing a National Institutes of Health grant progress report on the development of a human immunodeficiency virus (HIV) test for Specialty Labs, he became skeptical that HIV was the cause of acquired immunodeficiency syndrome (AIDS). In 1992, Mullis founded a business to sell pieces of jewelry containing the amplified DNA of deceased famous people such as Elvis Presley and Marilyn Monroe. That year, he also founded Atomic Tags in La Jolla, California. The venture sought to develop technology using atomic-force microscopy and bar-coded antibodies tagged with heavy metals to create highly multiplexed, parallel immunoassays.