Zheng, who was returning from dinner with his family, saw the victims of the robbery confront the suspects and believed it may have been another anti-Asian hate crime.
Zheng ran over to help and was stabbed four times by the suspected robbers. The three robbery victims were also stabbed, but are expected to be OK.
Police arrested 45-year-old William Smith for Zheng's murder, but sources said at least two other accomplices were on the loose.
Anyone with information is asked to call the NYPD's Crime Stoppers hotline at 1-800-577-TIPS (8477), or for Spanish, 1-888-57-PISTA (74782). You can also submit a tip via their website or on Twitter, @NYPDTips. All calls are kept confidential.
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