NEW: Repeat offender who had already been arrested several times this year, including for two assaults, killed an elderly man in an unprovoked attack in NYC. Hours before the attack, the NYPD had taken Rhamell Burke to a hospital for a psychiatric evaluation after he was reportedly acting irrationally on a Penn Station platform. Mysteriously, he was released just one hour later.A few hours later Burke shoved 76-year-old Ross Falzone, a retired teacher, to his death down subway stairs in Manhatta

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