Assistant Seattle Police Chief Jim Pugel said investigators recently received some "fairly credible information" that the woman, Kelsey Emily Collins, may have been buried in the Beacon Hill area after she went missing in early May 2009.
He said Collins had been forced into prostitution by a "particularly violent pimp" who kept her under his control through "coercion and violence."
"We have strong reason to believe she was murdered," he said.
Pugel said no one has heard from Collins since she vanished, but that police had recently come across information leading investigators to believe that Collins' remains were placed or buried in the woods near Jefferson Park Golf Course on Beacon Hill.
"We're looking for anything - hopefully the remains of Kelsey, and if not, any evidence that would show that she was here in the area or at least put here," he said.
So far, however, searchers and cadaver dogs brought in to help have found no trace of Collins.
Pugel said police haven't named a suspect in Collins' disappearance, but they have "strong suspicions" about who might be connected to her disappearance.
Collins disappeared May 9, 2009 - just a few days after her 18th birthday.
She is described as standing 5-feet-6-inches tall, weighing 155 pounds, with brown hair and green eyes. She went by her middle name of Emily.