Investigators said Tuesday that they are speaking to a person of interest who was seen on surveillance video with a duffel bag near the scene of a fatal shooting of a Brooklyn store owner Friday evening.

A man carrying a duffel bag was identified by police as one of four possible witnesses captured on surveillance video just after 6 p.m. Friday near the scene of the most recent killing.

They said these people were not necessarily suspects but may have seen something.

Police said Monday that they would like to speak with each of the four possible witnesses, and they said Tuesday that someone who fits the description of "John Doe Duffel Bag" is being questioned after walking into a precinct station house.

Vahidipour Rahmatollah, 78, died Friday after he was shot with a .22 caliber gun inside the She She Boutique on Flatbush Avenue.

Rahmatollah's shooting was connected to the shootings of Bay Ridge shop owner Mohamed Gebeli on July 6 and Bensonhurst store owner Isaac Kadare on August 2, as police said ballistics evidence confirmed the same gun was used to kill all three store owners.

The Federal Bureau of Investigation is providing assistance in the case to the New York City Police Department's Behavioral Analysis Unit.