NORTH ANDOVER

— A former professor at a Catholic college who is accused of viewing

photos of naked children

on a school-issued computer said he found the electronic images to be arousing, according to an FBI agent involved in the investigation.

Gary S. Spring, 61, the former chairman of Merrimack College's civil engineering department, admitted to "masturbating to images of child pornography," Special Agent Laurence A. Travaglia said in an affidavit included in a federal criminal complaint issued against Spring.

The Danvers resident was arrested Friday on child pornography charges after a search of his residence and college office confirmed that he possessed images of nude, prepubescent girls, federal officials said.

Authorities believe they have a solid case against the professor, who also served as administrator of the North Andover college's residential summer camp for middle- and high school-aged children.

Spring's phone number is unlisted and he could not be reached for comment. Some of his former colleagues either did not immediately respond to email questions or declined to comment when reached by phone Sunday.

Merrimack officials terminated Spring on Friday, scrubbing his online profile from the school's website and discontinuing his campus email account.

"Dr. Spring's access to email was barred upon his being placed on leave, and since he was terminated on Friday he can no longer be contacted through Merrimack," James A. Chiavelli II, the school's associate vice president of communications, said in an email message to MassLive / The Republican.

Spring admitted to viewing a series of pornographic images that "began with the children fully clothed and ended with them naked," Travaglia said.

U.S. District Court Magistrate Judge David H. Hennessy said he found enough evidence to sign off on the criminal complaint. "I have reviewed the images ... and I find probable cause to believe they depict minors engaging in sexually explicit conduct and child pornography," he said.

Merrimack College officials contacted authorities after discovering suspicious activity associated with a college-owned computer that was loaned to Spring. Further investigation determined that the computer was used to access child pornography, law enforcement officials said.

"The Merrimack College community is saddened by these disturbing allegations," Chiavelli said in a statement following Spring's arrest. College officials "brought this matter to the attention of law enforcement and support all efforts to investigate the full breadth and depth of this case," Chiavelli said.

Spring was placed on administrative leave and barred from campus at the outset of the investigation, which covered a period stretching from June until this month.

The criminal allegations are "not reflective of the institution, its members and its core values," Chiavelli said. "Our prayers today are for all victims of sexual exploitation, especially those unable to speak for themselves, and the college encourages everyone to immediately call potential abuse to the attention of the proper authorities."

Spring faces up to 20 years in prison, a possible lifetime probation sentence, and a $250,000 fine, though the actual punishment for federal crimes is typically less than the maximum penalties allowed by statute, according to U.S. Attorney Carmen M. Ortiz, whose office is handling the prosecution.

Anyone with information about the case is asked to call the U.S. Attorney's Office at (617) 748-3274.

Spring was being held until a detention hearing on Monday, according to a report by NECN, which did not cite a location for that hearing.