A 54-year-old man accused of fatally shooting a man in Costa Mesa two decades ago was behind bars Wednesday. Ismael Rosolio Martinez was charged 23 years ago with murder with a sentencing enhancement for the discharge of a gun causing death. He is accused of killing 20-year-old Ferdinand Eugenio Zamudio-Saucedo Oct. 11, 2003, according to court records. The shooting occurred about 1 p.m. in the 700 block of West Wilson Street, according to Roxi …