Remains dug up this week are those of the Green River killer's 40th victim, but the commander of the search for the nation's worst known serial killer says it's unlikely the find will lead to a breakthrough in the six-year-old case.

The bones and skull of Debra Lorraine Estes, a runaway who long had been feared a victim of the killer, were identified Tuesday through dental records.In addition to the 40 women known dead, eight missing women are listed as probable victims of the killer, who frequently dumped bodies in clusters in woods east and south of Seattle.

Estes, who was 15 when she vanished nearly six years ago, had been on the missing list until her remains were found Monday by workers digging post holes at a new apartment complex in Federal Way, a town between Seattle and Tacoma, said King County Police Sgt. Steve Davis.

"Like everything else that comes up, this answers one question and poses 100 more," said Capt. Robert Evans, commander of the King County Police Green River task force.

He said it was unlikely the discovery would yield any breakthroughs in the case.

The case takes its name from the Green River in south King County, where the bodies of the first five victims were found in the summer of 1982.

Estes' family declined to be interviewed Tuesday.

Estes, also known as Betty Lorraine Jones, was reported as a juvenile runaway by her parents in July 1982. She was last seen Sept. 20, 1982, along Pacific Highway South in Federal Way.