A 53-year-old man was fatally shot in front of his home in Oakland early this morning, a police spokesman said. At about 1:40 a.m., Cristorey Mariano was apparently returning from work to his home in the 5700 block of East 15th Avenue when he was shot, police Officer Jeff Thomason said.Oakland police responded to the area, as well as California Highway Patrol officers who were in the area and heard at least one gunshot, Thomason said. Officers found Mariano suffering from an apparent gunshot wound. He was pronounced dead at the scene, according to Thomason.No arrests have been made in connection with Mariano’s death. Homicide investigators are working to establish a motive for the shooting, Thomason said.