We analyze the partial rate asymmetry in $B^{pm} to P {bar P} pi^{pm}$ decays ($ P = pi^+, K ^+, pi^0, eta$) which results from the interference of the nonresonant decay amplitude and the resonant amplitude for $B^{pm} to chi_{c0} pi^{pm} $ followed by the decay $chi_{c0} to P {bar P} $. The CP violating phase $gamma$ can be extracted from the measured asymmetry. We find that the partial rate asymmetry for $B^pm to pi^+ pi^- pi^pm$ is $0.33~sin gamma$, while for $B^pm to K^+ K^-pi^pm$ it amounts $0.45~ sin gamma$.