Police say a man was killed in a shooting incident late Sunday night in Lincoln.  An investigation continues into the death of 19 year old Naif Al-Kazahy, whose address is listed as 1228 South 23rd Street in Lincoln.  It happened just before 11:30 p.m. near South 14th and Sumner.   According to police, Al-Kazahy was walking with his brother and friends near a house at 1328 South Sumner Street when an argument broke out with a group of people.  Lincoln Police Chief Jim Peschong said the incident escalated to a physical altercation and a shotgun blast struck Al-Kazahy in the chest.   Police say Al-Kazahy's brother and friends took him away from the scene to 1415 Sumner Street, where authorities were called.  Al-Kazahy was taken to Bryan LGH West Hospital where he died from his injuries.  Officers are still looking for a suspect and others that witnessed the shooting.