Washington ? Searchers on Wednesday returned to a site near Kent where confessed Green River serial killer Gary Ridgway said he left a body.

About a dozen law enforcement officers raked along a steep hillside, removing ivy and trash. But, by day’s end, they came up empty-handed — finding little more than beer bottles and plastic cups.

“There’s got to be bones out here someplace,” Detective Tony McNabb said. “It’s just a question of finding them.”

Ridgway pleaded guilty last week to killing 48 women, most of them in the early 1980s. In a plea agreement that spared him the death penalty, he has cooperated with authorities in recent months to find victims whose bodies have not yet been located.

Beginning in 1982, Ridgway picked up prostitutes, strangling them and molesting their bodies, which he left in the Green River and other inconspicuous dump sites around Seattle.