The chief operating officer at the National Children’s Museum in Washington, D.C., is facing charges that he traded images of child pornography.

Robert Singer, 49, was arrested yesterday in Virginia as part of a sting operation run by a Bronx detective with the New York Police Department. A call for comment at Mr. Singer’s home in Falls Church, Va., was not returned. His lawyer did not immediately return a call left at his office.

“We are horrified by the charges” and will cooperate with the investigation, the museum said in a statement posted on its Web site. While the statement did not disclose Mr. Singer’s position at the museum, one source told The New York Sun that he is the chief operating officer.

Mr. Singer sent about 80 images containing child pornography to the detective and others in August and September, according to a criminal complaint unsealed yesterday in U.S. District Court in Manhattan.

Mr. Singer contacted the NYPD detective in an America Online chat room known to authorities as a place where pornography is traded, the criminal complaint said. The detective was posing in the chat room both as a 33-year-old woman and a 12-year-old girl, and Mr. Singer sent e-mail messages to each containing several images depicting children engaged in sexual acts, the criminal complaint said.

Presented with a search warrant last month, AOL gave federal authorities a disk containing e-mails from an account linked to Mr. Singer’s name, the complaint said. Mr. Singer is charged with distributing child pornography in interstate commerce and faces up to 40 years in prison if convicted.