ST. PETERSBURG — An argument between two men a month ago resulted in one being shot to death. On Saturday, police arrested the other man in the altercation. Melvin Benjamin is charged with second-degree murder in the case, authorities said.St. Petersburg police arrested Benjamin, 60, in the 1100 block of Newton Avenue S early Saturday. He was being held in the Pinellas County Jail.On May 1, Benjamin and Christopher Mackey, 27, were arguing at 1040 Melrose Ave. S when Benjamin pulled out a firearm and shot Mackey in the upper chest, witnesses told investigators.Mackey was taken to Bayfront Health St. Petersburg, where he died the same day. The cause of the argument and the reason for the shooting remain unclear. Authorities on Saturday morning were interviewing Benjamin at the Pinellas County Jail.