Chicago police are asking for help identifying a man who shot and killed another man during an argument last week in Lincoln Park.Around 4 p.m. Wednesday, a 34-year-old man was “exhibiting erratic and dangerous behavior” in the 2400 block of North Clark Street when he instigated an argument with a group of people, one of whom pulled out a gun and fired shots, Chicago police and Ald. Timmy Knudsen (43rd) said.The 34-year-old suffered a gunshot wound to the chest and was taken initially in critical condition to Illinois Masonic Medical Center. The still-unidentified man was pronounced dead about 1:20 p.m. Monday, according to the Cook County medical examiner’s office. The gunman fled the scene. Footage from a surveillance camera released Tuesday by police shows the alleged gunman dressed in all black.Anyone with information is urged to contact Area 3 detectives at (312) 744-8261. Anonymous tips can be submitted at cpdtip.com.