A longtime District pediatrician, who served families in some of the city’s poorest neighborhoods, pleaded guilty Thursday to possessing child pornography.

Robert P. Dickey admitted in federal court that he had downloaded and viewed graphic sexual images of young children in his Southeast Washington office where he was arrested in May.

“Dr. Dickey is trying to bring resolution to this and let people in the community who were affected heal,” his attorney Marlon C. Griffith said after the plea hearing in U.S. District Court in Washington.

Dickey, 74, faces prison time ranging from 57 to 71 months, according to federal sentencing guidelines.

Assistant U.S. Attorney Ari B. Redbord said that a search of Dickey’s e-mail account and computer had turned up more than 100 pornographic images. The pediatrician was viewing a Web site that featured child pornography when the FBI arrested Dickey in his office after being tipped off by the National Center for Missing and Exploited Children.

“Dr. Dickey was entrusted to care for the well-being of children, but he instead chose to collect images of their sexual exploitation,” U.S. Attorney Ronald C. Machen Jr. said in a statement.

“Victims of child pornography are harmed when images of their abuse are swapped over the Internet for years, haunting the victims long after their initial abuse.

Prosecutors have said there is no evidence that Dickey’s patients were the subject of the images or that he had abused any of them.

At an earlier detention hearing, Dickey was joined by his wife, children and some parents of patients who testified about Dickey’s commitment to the community, where he had worked since the late 1970s.

Griffith said he expects several people to testify on Dickey’s behalf at his sentencing hearing set for Dec. 17.