Snoqualmie police have found the Clyde Hill man who vanished Monday after a visit to Mount Si Golf Course.

Now, investigators are trying to learn why 64-year-old Wayne Lee Singleton disappeared for four days.

Singleton reappeared Thursday afternoon in North Bend, several miles and one city away from where officers found his car.

At 1 p.m. Thursday, Singleton phoned his wife, asking that she pick him up near Rattlesnake Lake. He was found on Cedar Falls Road by Snoqualmie police, then taken to Snoqualmie Valley Hospital for an evaluation. Afterwards, he was taken to Mercer Island to speak to investigators about his disappearance, then went home.

Snoqualmie Police Spokeswoman Becky Munson said Singleton is cooperating with detectives, and that the investigation is in progress.

Singleton was reported missing on Tuesday after he failed to return home from a golf game the previous day. He had last been seen eating lunch at the Mount Si course restaurant. North Bend police found his car, a Mercedes S-550, parked near the course.

Snoqualmie Police, King County Search and Rescue and detectives from the Major Crimes Task Force, a coalition of county and city police agencies, launched a search in the vicinity of the course, which includes marshy woodlands adjacent to the Snoqualmie River. Police dogs and a helicopter were called to the scene, but failed to find him.

When he was found, Singleton appeared healthy and little worse for wear, police said.

Singleton requires blood pressure medication daily.

Mount Si Golf Course staff said Singleton usually plays at the course a few times a year.