SEATTLE, Washington (AFP) — Searchers in the Northern Cascade mountains have found two packs belonging to the son of boxing promoter Bob Arum, but are still seeking the missing climber, authorities said Thursday.

John Arum, a 49-year-old environmental lawyer and an experienced climber, was reported missing on Monday when he failed to return from an attempt to scale the 8,515-foot Storm King peak northeast of Seattle.

North Cascades National Park spokeswoman Kerry Olson said Thursday that a backpack belonging to Arum was found late Wednesday afternoon by ground searchers some 900 feet below the summit of the mountain.

Olson said the backpack was along a climbing route, and “it looked as though it was placed there.”

A daypack was found in an area that suggested it fell because the terrain is too difficult, Olson said.

Olson said a dozen searchers aided by two helicopters resumed the hunt for Arum on Thursday morning. On Friday, search dogs will be used.

Bob Arum was in Los Angeles Tuesday for the first of three stops on a tour to promote the November 13 Manny Pacquiao and Antonio Margarito junior middleweight title fight. He left that same day for Washington state after learning his son was missing.

The Pacquiao fight will take place at November 13 at Cowboys Stadium in Dallas.