On April 21, 1992, California received wide national attention when Robert
Alton Harris was executed in the gas chamber at San Quentin. Harris's execu
tion marked a reintroduction of the death penalty in California after a 25-
year moratorium. We use weekly time-series data on the level and type of cr
iminal homicide incidents in the state from 1989 through 1995 to exploit th
e quasi-experimental qualities of this naturally occurring "experiment," an
d assess the impact of Harris's execution on the incidence of homicide. As
in several recent studies, we disaggregate criminal homicides into forms of
murder highly likely to be affected by capital punishment: felony-murders
of nonstrangers, for which we predict a deterrent effect, and argument-murd
ers of strangers, for which we predict a brutalization effect. On the basis
of an autoregressive integrated moving-average approach to time-series ana
lysis, we find (as predicted) a significant decline in the level of nonstra
nger felony-murders and a significant increase in the level of argument-bas
ed murders of strangers in the period following the execution. Moreover, th
e increase in argument-based stranger murders associated with the Harris ex
ecution endured across a subsequent execution period, while the decline in
nonstranger felony-murders shifted to the subsequent execution.