  Based on 58 million BESII J/psi events, the bar{K}^*(892)^0K^+pi^- channel in
K^+K^-pi^+pi^- is studied. A clear low mass enhancement in the invariant mass
spectrum of K^+pi^- is observed. The low mass enhancement does not come from
background of other J/psi decay channels, nor from phase space. Two independent
partial wave analyses have been performed. Both analyses favor that the low
mass enhancement is the kappa, an isospinor scalar resonant state. The average
mass and width of the kappa in the two analyses are 878 +- 23^{+64}_{-55}
MeV/c^2 and 499 +- 52^{+55}_{-87} MeV/c^2, respectively, corresponding to a
pole at (841 +- 30^{+81}_{-73}) - i(309 +- 45^{+48}_{-72}) MeV/c^2.
