Three men first approached the 17 year old, demanding money.
Surveillance video shows them punching the teen as he tried to escape.
It happened earlier this month on East Gun Hill Road in the Williamsbridge section.
the suspects were able to grab his backpack, which had more than $1500 worth of items inside.
The suspects fled with 2 other men.
Police are asking for the public's help tracking down all five suspects.
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 tips by visiting the CrimeStoppers website at crimestoppers.nypdonline.org or by messaging on Twitter @NYPDTips.
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