Edward Y. Chen admitted in a Fairfax County courtroom yesterday that he shot his parents and older brother to death inside their Great Falls home in 1995, then left their bodies inside the house for nearly four years.

Shortly after pleading guilty to three counts of first-degree murder, Chen, 27, was sentenced to 36 years in prison.

The combined plea and sentencing hearing brought an abrupt end to a case that unfolded just as suddenly nine months ago, when Chen's ex-girlfriend called Fairfax County police and revealed Chen's secret. The woman told a police dispatcher that on Aug. 17, 1995, when Chen was 19, he shot his father, Wu-Hung Chen, 53; his mother, Yeh-Mei Chen, 52; and his brother, Raymond, 25.

Chen then locked up the house and avoided suspicion by making sure that the lawn and exterior were maintained. He kept his family's remains there until 1999, when a pipe burst and the house flooded. He and a friend dumped the bodies in the Chesapeake Bay, and Chen sold the house, keeping the crime not just unsolved but unknown.

The elder Chens lived mostly in Taiwan and were not reported missing. Chen told relatives in Taiwan that his family had died in a car accident in the United States. But after the March 19 phone call to police by Chen's ex-girlfriend, Vickie Henry, detectives quickly investigated and arrested Chen on March 29. That night, he admitted to investigators that he had purchased a .30-30 Winchester rifle, went into his family members' bedrooms in the middle of the night and shot them.

"And one night I really just lost my nerve, lost my mind and I did it," Chen told Fairfax detectives. "I shot them. . . . My brother and my parents." Chen said he shot them because they were trying to break up his relationship with his girlfriend.

Fairfax County Circuit Court Judge Jonathan C. Thacher ruled last month that Chen's confession was inadmissible because he had told detectives "I don't want to talk about it" before relating details of the crime. But Fairfax Commonwealth's Attorney Robert F. Horan still had three key witnesses: Chen's ex-wife, Mandy Chen, who had seen the bodies; Chen's friend Michael Reese, who helped him dispose of the bodies; and Henry, whom Chen had told about the killings and who made a tape-recorded phone call to Chen for the police shortly before Chen's arrest.

With a trial set for yesterday, Chen's attorneys, Peter D. Greenspun and Jonathan Shapiro, negotiated a deal. Horan had announced that he would not seek the death penalty, but Chen still could have faced three life sentences if convicted by a jury. Instead, both sides agreed that the middle point of Virginia's suggested sentencing guidelines, which ranged from 26 to 45 years, was appropriate.

"I want to apologize to my family and friends," Chen said in court, speaking publicly for the first time, "especially my daughter, for what I put them through. I hope that by not going to trial, I saved everyone more pain and suffering. I feel very guilty for what I did."

Greenspun said that Chen will serve about 30 years. Although Virginia does not have parole, it does reduce sentences slightly for good behavior. Chen will be eligible for geriatric release when he is 60, after serving about 33 years.

"He can't get out until he's 60," Horan said. "That's satisfactory."

Horan said he would not seek charges against Chen's ex-wife, who saw the bodies but did not report the killings, or Reese. He said that Mandy Chen had not committed a crime and that the statute of limitations had expired for Reese's part in the crime.

The bodies have not been found.

Chen's father owned a heating and ventilation company in Taipei and sent his sons to Northern Virginia for their education. The brothers lived in a house in Herndon, and each graduated from Herndon High School. Raymond Chen began working in real estate, including overseeing five Fairfax properties his parents bought, and Edward Chen enrolled at the University of Virginia.

Shortly after, Edward Chen began dating Mandy Kolbe. His parents disapproved, Horan said, and in summer 1995, they took Edward Chen back to Taiwan and placed him in a mental institution.

Edward Chen returned with his family to Great Falls and killed them so that he could continue dating Kolbe, Horan said. He revealed the crime to Kolbe, but she said she didn't report it because she both loved and feared Chen. The couple soon had a child, married and divorced. Their daughter is now 6.

In 1998, according to court records, Chen assumed his brother's identity and began selling the family's homes.

With a friend, Edward Y. Chen dumped the bodies of his parents and brother in the Chesapeake Bay.