It took a jury only 35 minutes to return a guilty verdict in the 2008 execution-style slaying of a 19-year-old man outside a northeast Philadelphia car wash.
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The Philadelphia Inquirer said 31-year-old Omar Sharif Cash was found guilty of first-degree murder Thursday.
Cash claimed shooting Muliek Ronald Brown in the back of the head as Brown polished the wheel rims of his car was self-defense.
Cash is already serving a life-without-parole sentence in Bucks County for murdering a man he carjacked and repeatedly raping the man's girlfriend before and after the 2008 slaying.
The Philadelphia jury didn't know about that case during the trial. They will be told Tuesday, when they return to court to decide if Cash should be sentenced to death or life without parole.