Walter Massey, then a physicist at Argonne National Laboratory, was fatally shot on a hotel balcony in Memphis, Tennessee, in 1968. At the time, Dr. King Jr. was a rising star in the study of theoretical condensed matter, how liquids and solids behave. In his most noteworthy calculation, he corrected a longstanding theory of superfluid helium established by Lev Landau, winner of a Nobel Prize in Physics. But Dr.