PORTLAND — A search resumed Friday in Southern Oregon for a couple and their adult son who disappeared after leaving their campsite to pick mushrooms.

Belinda and Daniel Conne, both 47, and their 25-year-old son, Michael, were last seen Sunday at their campsite on the Rogue River. They did not return to a camping trailer where they left two dogs.

Their Jeep was found on a logging road.

Searchers recovered a can of Pepsi, mushroom-picking buckets and toilet paper Friday while searching a 4-square-mile area of rugged coastal forest. The search has involved three Southern Oregon counties and one county in California.

On Friday, Bishop put out a mutual-aid request statewide, requesting any search-and-rescue resources that other counties are able to send.

He said authorities have no reason to suspect foul play in the disappearances.

“At this point, there is no reason or indication to believe that there is foul play involved,” Bishop said.

The topography of the coastal range makes it a difficult place to search. Steep, craggy hills covered in thick vegetation make for unsure footing and limited lines of sight.

Searchers planned to return Saturday, Bishop said.

Joe Dykes, who works at the Huntley Park campsite where they were staying, said the Connes arrived at the campsite in July and their son got there later.

“They were really nice people, a nice family,” Dykes said. “They mentioned working back in Oklahoma, making good money, doing I don’t know what kind of work.”

The campsite has no electricity and limited running water. Dykes said the family lived in a recreational vehicle with a trailer attachment.

A helicopter flown by a volunteer flew low and slow over the area Thursday but was unable to see tracks or traces of the family. On the ground, more than 40 searchers and four canine units searched a 4-square-mile area without success.