D.C. Police Chief Cathy Lanier plans to discuss the death of Joyce Chiang at Friday's news conference.
Chiang was an Immigration and Naturalization Service attorney who disappeared in January 1999. Her body was found that April on the banks of the Potomac River in Virginia.
Police initially believed Chiang's death was a suicide. But Chiang's brother, Roger, says police will announce they've reclassified her death as a homicide.
He says two men have been implicated in connection with his sister's death, though no one has been charged. He also says one man is imprisoned in Maryland. The other was deported to Africa several years ago.
A spokesman for the U.S. Attorney's office says the case remains under investigation.