Residents shut themselves in after dark, drew curtains and answered callers warily as police hunted for a gunman believed responsible for four shootings in as many nights. The first victim was killed outside his auto customizing shop on Monday. Three men were wounded by shots fired into their homes on each of the next three nights. Police on Friday had patrols closely watching neighborhoods in this township of 23,000 people on Long Island. ``We can only assume that the killer has gotten scared because of the extra patrols, or else he's taken the night off. We just don't know,'' Detective Sgt. William Armstrong of the Southampton police said late Friday. The shootings have enough in common to point to one sniper, but police so far say they haven't found a common thread that would point to motive. All the shootings have occurred after dark, most around dinner time, within a two-mile radius in the towns of Southampton and Riverhead. The two towns are about 75 miles east of New York City and near the exclusive beach communities favored by the city's wealthy. The victims, all blue-collar men in their 30s, were shot with either a small-caliber rifle or a lightweight shotgun. Friends and relatives described them all as hard-working family men and were at a loss to suggest a motive. ``It's scary,'' said Barbara Bouchard, who lives next door to one of the victims. ``This is stuff you hear about in New York City. Around here, the most serious thing is they catch people shoplifting.'' An anonymous caller believed to have been the gunman contacted Riverhead police after the first shooting Monday and said, ``death to drug dealers and crooked cops,'' according to a source involved in the investigation who spoke on condition of anonymity. A similar call came after the second shooting on Tuesday, he said. But police said none of the victims was known to have dealt drugs and they apparently did not know one another. ``There is a definite link with the four,'' said the source. ``We think there is a reason for these shootings, a perverted type of thing.'' Southhampton police Chief Conrad Teller said the victims appeared to have been specific targets and not chosen at random. But, he said, ``we have nothing concrete to connect them.''