A 14-year-old Northeast Washington youth has told D.C. police that he was sexually abused by a man who was able to pull him out of school by posing as his godfather, according to court papers.

Ralph J. Nelson, 40, was arrested Friday after the youth told police about a series of alleged incidents that took place from June 2004 to October, authorities said. Nelson was charged with first-degree child sexual abuse and jailed pending a hearing scheduled for today in D.C. Superior Court.

Police described Nelson in charging papers as a neighbor of the youth. They said the incidents began shortly after he met the teenager and took place at Nelson's apartment on 12th Street NE, typically after Nelson showed the youth pornographic movies. The charging documents quote the youth as saying that Nelson did "nasty" things to him and that the abuse took place on numerous occasions.

Authorities said the teenager's family did not know Nelson.

The youth, a student at Shaw Junior High School, told police that Nelson misled school officials by posing as his godfather, the charging papers stated. As recently as last Wednesday, the teenager told police, Nelson went to the Northwest Washington school and signed the youth out of class.

The charging papers do not reveal whether any of the alleged abuse took place during periods when the boy should have been in school.

School officials are investigating whether Nelson did sign the youth out of Shaw and, if so, how he was able to carry out the ruse.

Alexis Moore, a D.C. public schools spokeswoman, said yesterday that she did not know whether Nelson's name was on the teenager's enrollment form.

"It is our policy that the name of a parent, guardian or appointed representative has to be on the child's enrollment form," Moore said. "If your name is not there, you have no permission or access to the child or the child's record."

The allegations came to light after an anonymous caller alerted police, authorities said. Detectives interviewed the youth Dec. 1 and arrested Nelson the next day.