50-year-old Nagy admitted that he obtained the visual depictions of children engaged in sexually explicit conduct by downloading them from emails onto his computer at his former residence in Ben Lomond, a community in Santa Cruz County, Russoniello said in a prepared statement.
The litany of images included depictions of prepubescent minors and images portraying sadistic or masochistic conduct, the U.S. Attorney's Office said.
Nagy had been previously charged by indictment with possession of child pornography, the statement said. He has been in custody since his initial appearance in court on that charge.
Nagy's sentencing is scheduled for Oct. 21 before U.S. District Court Judge Jeremy Fogel in San Jose. The maximum statutory penalty he faces for each violating count is 10 years in jail, a fine of $250,000, and potential restitution to the victims, the U.S. Attorney's Office said in a statement.
Assistant U.S. Attorney Joseph Fazioli is prosecuting the case with assistance from Kamille Singh. The prosecution is the result of a joint investigation effort by the U.S. Immigration and Customs Enforcement and Homeland Security, the statement said.