Friends and family planned a private remembrance today for Joyce Chiang, one year after the petite, 28-year-old Immigration and Naturalization Service lawyer disappeared from a wintry corner near Dupont Circle and was later found dead in the Potomac River.

The search for Chiang, which ended when the body of the Georgetown University Law School graduate was pulled from the water in April, transfixed city residents and became the focus of a near-nightly vigil by local television stations.

On Friday, the FBI appealed again to the public for new leads in the mystery and declared that the agency "remains determined in its efforts to solve this case."

"There's always an eternal flame inside me and my mom and the rest of my family that we can find out what happened to Joyce the night she disappeared or the subsequent nights until her death," said brother Roger Chiang, 26, of Arlington, a spokesman for Chiang's mother, Judy, and two other brothers, John and Robert.

Roger Chiang said: "1999 was a long, tough year. We just celebrated the holidays, and we did it without Joyce's physical presence. That was the hardest part of the holidays." Most of the family lives in Chatsworth, Calif.

Joyce Chiang was last seen near Dupont Circle getting a cup of tea from a Starbucks coffee shop on Saturday, Jan. 9. A friend dropped her off after dinner, blocks from the apartment she shared with her brother.

Chiang's government identification card was found the next day in Anacostia Park. A canoeist discovered her decomposing body on April 1 in the Mount Vernon area of Fairfax County. Medical examiners could not determine the cause of death.

Roger Chiang, who is advance director for Housing and Urban Development Secretary Andrew M. Cuomo, cited a $50,000 reward for information. "The FBI and my family still believe that somebody knows something and can come forward and help us solve this case," he said.

In addition to reward money, Chiang's death has spurred memorial funds in her name at Georgetown University Law School, where she graduated from the evening division in 1995, and Smith College, where she was student government president in 1992.

The INS has established an employee customer service award in her name, Roger Chiang said.

"I've talked to so many people who say they think about it, if not daily or weekly, they just think about it constantly," Chiang said. "It just seems an innocent situation, her walking down the street and she just disappeared."

The death of Chiang, an employee of INS Commissioner Doris M. Meissner and former aide to Rep. Howard L. Berman (D-Calif.), has been assigned to the FBI squad in charge of assaults to a federal officer. The FBI said calls to 202-278-2382 would be handled confidentially.

CAPTION: Joyce Chiang, 28, disappeared last year from the Dupont Circle area.