A man serving a prison sentence in a sexual assault case has been indicted on a charge of murdering a 10-year-old Severn, Md. girl whose nude, battered body was found in 1971 beneath rubble at a dump near Baltimore-Washington International Airport.

Anne Arundel, County police said Richard Miles Chaney, 36, who is serving a four-year sentence at a work camp in Jessup, Md., told two county detectives last week he killed Elizabeth Ann Metzler in December, 1971.

Chaney is serving his sentence for incest with his 7-year-old daughter in 1975.

Police said Chaney, whom they described as a "shy, quiet" man, has been a suspect in the Metzler girl's slaying for the past two years. They said he apparently decided to make a statement when he saw county Dets. Gordon March and Thomas Mock at the work camp last week. Chaney knew March, who once was a patrolman in Odenton where Chaney worked in an auto repair shop police said.

Chaney approached the two officers and asked to see them privately, according to March. "He said he just wanted to get it off his chest . . . He said it was something he was living with for a long time . . . He has a lot of remorse," March said.

According to police, Chaney told the two detectives that problems at home as well as a heavy drinking problem provoked an "emotional buildup" that led to the slaying.

The blonde, 10-year-old, youngest of five children, disappeared Dec. 6, 1971, after leaving her elementary school, where she was in the fifth grade. A massive search located her clothes, school books and lunch box at sites several miles part. Her body was found on the third day of the search.

Chaney, who lived about 2 1/2 miles from the Metzler girl in the Baltimore suburbs, denied knowing the girl according to detectives.

Reached by phone, Agnes Metzler, Elizabeth's mother, told a reporter, "The incident has never really left up, but this (the indictment) brings it all back up again. It's not the easiest thing to go through."