The principal of a charter school on Chicago's North Side has been arrested on charges of possessing child pornography, federal officials said Monday.

Joseph Thomas Nurek, 54, was arrested Friday in his home by immigration and customs agents, officials said. They said they found more than 100 images of child pornography on the computer and more on CD-ROMs, VHS videos, DVDs and floppy discs.

Magazines discovered in a closet also contained pornographic images, officials said.

The images showed boys as young as 12 years old performing sexual acts, according to an affidavit filed by the Department of Homeland Security, Immigration and Customs Enforcement (search).

Nurek is principal of the West Belden Campus of the Chicago International Charter School (search), which has students ranging from kindergarten through seventh grade. It is operated by American Quality Schools (search), a private company.

Federal officials initially described Nurek in a news release announcing the arrest as "a Chicago public schools principal." They later said the school has no relationship with the Chicago Public Schools.

Charter schools operate independently of the school districts in their area under state-issued charters.

An attorney for the school, Leo J. Athas, said Nurek was hired 4 years ago as an administrator and was named principal of the school about 18 months ago.

Athas said there had been no complaints from parents about Nurek and that a background check before he had been hired turned up no evidence of involvement in child pornography.

"We've already contacted the parents," Athas said. "We are quite confident that the students in our charge are safe and that there was no problem."

Athas said Nurek has been suspended without pay pending the outcome of the investigation.

Federal prosecutors said the investigation was ongoing.

Nurek was taken into custody Friday night and appeared briefly before U.S. Magistrate Judge Arlander Keys on Saturday, officials said. They said another hearing was scheduled for Tuesday.

Nurek was being held in the government's Metropolitan Correctional Center.

Possession of child pornography carries a maximum sentence of five years in prison and a fine of $250,000.

Nurek's attorney, Gabe Plotkin, was not reached immediately for comment. A message was left on his answering machine.