WEST ISLIP - Police are asking for the public's help in finding the hit-and-run driver who killed a Suffolk man.Officials are offering a $5,000 reward for information leading to the driver who fatally struck 27-year-old Jason Nelson, of Brightwaters.Nelson was hit by a car outside his home on Sandra Avenue in West Islip on July 2. Police now believe that Nelson may have had an altercation with someone in the car before he was killed. Anyone with information is urged to call Suffolk Crime Stoppers at 1-800-220-TIPS.