STAMFORD - Stamford police say they have intensified their search for the man who shot and killed another man outside La Fabolosa food mart.

The incident happened near the intersection of Pacific and Ludlow streets at around 8:30 p.m. Thursday night.

Police say the gunman walked up behind 46-year-old victim William James and shot him in the head before fleeing the scene. James was pronounced dead at the hospital.

Police search dogs were used today to canvass the area for several hours but have not found anyone.

Police say this is a difficult investigation because they don't have a good description of the gunman.

Despite all of the people who were outside La Fabolosa food mart who may have seen the shooting, witnesses are reluctant to give up any information.

Police say the next step in their investigation is to go through local security video to see if they can make any sort of identification on a suspect.