SACRAMENTO, Calif. — The two brothers charged with multiple murders in the April 3 mass shooting in downtown Sacramento appeared in court Thursday afternoon in a case that could lead to a death penalty prosecution against them. Smiley Martin, 27, and Dandrae Martin, 26, both face three murder counts stemming from the gang shootout that erupted at 2 a.m. at 10th and K streets a month ago and left a total of six people dead and 12 wounded. A third suspect, Mtula Payton, 27, also has been charged with three counts of murder, as well as unemployment insurance fraud, but remains a fugitive. Smiley …