A maintenance help-desk employee at the Naval Academy has been charged with possessing child pornography and posing as a 12-year-old on the Internet to solicit photographs of nude children, state prosecutors said yesterday.

David N. Sprachner, 44, of Glen Burnie apologized at a bail hearing in Annapolis yesterday for what he said was a "stupid, sick mistake."

But his request to be set free until trial was rejected by District Judge Vincent A. Mulieri after prosecutors warned that Sprachner shares a small apartment with a couple and their four children. Authorities presented no evidence that Sprachner involved those children, ages 2 to 16, in any of the alleged misconduct.

Sprachner was arrested at his apartment on Glen Ridge Circle on Tuesday evening after a three-month investigation that began when a co-worker reported seeing sexually explicit photos of children on Sprach- ner's desktop computer at the academy.

A civilian employee, Sprachner had worked at the military college's public works office since March 1998, answering a hot line for reporting maintenance problems such as leaky faucets and broken radiators.

Agents with the Naval Criminal Investigative Service and the Anne Arundel County state's attorney's office seized computers from his home and office and found digital images and printouts of boys and girls "in various positions of a suggestive sexual nature," according to court documents.

Authorities said in court papers that Sprachner admitted to posing as a 12-year-old in chat rooms meant for preteen children. Authorities said he told them that during the past two and a half years, he had asked for and received more than 50 pornographic images of children.

David Cordle, chief investigator for the county state's attorney, said in an interview that evidence indicated that Sprachner also exchanged such images through U.S. mail.

The Naval Academy suspended Sprachner without pay after his arrest Tuesday, but officials there had no comment about the case.

Sprachner, who is single, was charged with one count each of possession and distribution of child pornography.

Sprachner spoke to Mulieri at yesterday's bail hearing through a live television link from the county jail in Annapolis. "I'm scared to death," Sprachner said, lowering his head and pinching the bridge of his nose. "I made a stupid, sick mistake, and I'm more sorry that you could imagine."

But the judge refused to free Sprachner on his own recognizance or lower bail, set at $75,000. He said that if Sprachner made bail, he was to stay away from children and keep off the Internet.

No trial date has been set.