New York Police officials said on Monday they are focusing the
investigation into the murders of three Brooklyn store owners on
a single man who was captured on surveillance camera near one of
the crime scenes.  The man—who hasn't been identified and was
dubbed "John Doe Duffel Bag" by the NYPD—is seen on the video
wearing an overcoat and carrying a dark bag. He appears to have
a mustache and thinning hair.   Based on certain patterns and
ballistics evidence recovered at the scene, police officials
believe Mr. Vahidipour was killed by the same gunman who fatally
shot two other Brooklyn shopkeepers in July and August.  In each
incident, .22-caliber shell casings were recovered, likely fired
from a rifle—which is why the duffel bag in the suspect's
possession is of such interest, a law-enforcement official said.
The bag can be used to conceal the conspicuous weapon, the
official said.  All three men have Middle Eastern backgrounds,
and their stores shared similar characteristics: The stores were
small, none of