Video shows the robber approach an employee with a bouquet of flowers inside the Boost Mobile store on East 170th Street Monday afternoon.
Police say he then put the flowers down and pulled out an unknown object and demanded cash.
When she refused, he grabbed her by the arm and neck and forced her to the back of the store.
That's where he stole $16,000 from the safe before taking off westbound on 170th Street towards Jerome Avenue.
The employee was not injured.
Anyone with information in regard to the identity of this individual is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782).
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