A 14-year-old Fairfax County youth died early Thursday morning after apparently hanging himself in his cell at the Northern Virginia Juvenile Detention Center in Alexandria, authorities said yesterday. Officials said it was the first such incident at the facility since it opened 20 years ago.

Authorities learned after the hanging that the youth, whose name was withheld by Alexandria police investigating the incident, had told two friends he was "going to try to hurt himself" in an effort to get transferred to a hospital and "to run from the detention center," according to Jay Melvin, the center's director.

"My gut feeling," Melvin said, "is that it [the death] was an accident -- a very unfortunate accident."

The youth had been sent to the regional facility for juvenile offenders and youths awaiting trial by Fairfax authorities a month ago. He was scheduled to appear in court within the next few weeks.

Melvin said the 14-year-old "was the last kid I would have suspected" of wanting to kill himself of the 43 youths housed at the facility. "There was no indication of crisis, no depression, no withdrawal. In fact, what you saw was a typical teen-age kid in detention -- he participated in athletics in the afternoon and in the evening program. . . . I can tell you unequivocally: Absolutely no mistake was made the other night. We probably went beyond what you would find in any other institution" in terms of taking precautions.

"I feel helpless in this case. Kids will go into a crisis unpredictably. You never know what's going on inside their heads," Melvin continued.

Mike Hanley, the center's assistant director, said the 14-year-old hanged himself within five minutes after he was checked into his cell at 12:10 a.m. He was found hanging from a bedsheet that had been tied to a steel grid covering a light fixture on the 10-foot-high ceiling, Hanley said, and the discovery was made by one of three staff members who make frequent checks on the 43 beds in separate male and female dormitories.

The staff member summoned other workers trained in cardio-pulmonary resuscitation, Hanley said, and the youth was taken to Alexandria Hospital where he died at 9:45 the same morning.

Fairfax authorities said the youth had been jailed for a number of alleged offenses, but were unable immediately to furnish details.

Hanley called the death "very tragic" but said, "I don't know if suicides are preventable."

The facility, located near the Landmark area in Alexandria's west end, was built 20 years ago in response to a public outcry against incarcerating juveniles along with adults in local jails. It was designed to permit its staff to monitor the acitivities of the juveniles housed there.

At point, staff members are required to check on inmates in their cells at least every 15 minutes. The cells have windows in their doors and microphones that are monitored at a central office.

The hanging was the third in a Northern Virginia detention facility this year and the second in the Washington area in less than two weeks. A 24-year-old District of Columbia man awaiting trial on forgery and larceny charges was found hanged in the Arlington Jail Jan. 25, 17 days after a mortgage banker's son hanged himself in the same facility.

Nine days ago, a 25-year-old theft suspect hanged himself in a special mental observation cell at the Prince George's County Jail in Upper Marlboro, the second prisoner suicide in that county in less than two months.