1980s Philadelphia mob boss Nicky Scarfo will be the subject of an hour-long Biography Channel special next month. "We tried to paint the picture of not only the mobster, but who he was as a person," says Samantha Nisenboim, associate producer for Chicago's Towers Productions, which is behind the special. "That was difficult because he kept his personal life so private." "Little Nicky," who's now 79, is a guest of the U.S. Penitentiary in Atlanta and did not participate in the special, which airs at 9 p.m. on Dec. 19. "We reached out to Nicky Scarfo, but the federal penitentiary intervened and wouldn't let him know," Nisenboim said last night. Retired Philadelphia police captain Frank Friel, retired FBI agents Michael Leyden and James Darcy, and retired federal prosecutor Lou Pichini are among those who were interviewed for the special. An unidentified mob associate is also interviewed as were South Philadelphia author/historian Celeste Morello, who wrote the "Before Bruno" series about the Philly mob, and Inquirer reporter George Anastasia, who has written several books about Scarfo and the mob.