RESTON, Va. (FOX 5 DC) - A Fairfax County children’s entertainer – who goes by the stage name “Mr. Knick Knack” - is under arrest after detectives allegedly found multiple child pornography files in his possession. Steven Rossi, 58, of Reston is charged with 10 counts of felony possession of child pornography. Police began investigating Rossi on April 18 after the Fairfax County police department received a tip.