By late afternoon, the search began to wrap up with no sign of the boy - and police began to show disappointment with the lack of progress.
"Every hour that passes, this case becomes more and more disappointing for us that we haven't found something to lead to his discovery yet," Bellevue Police Maj. Mike Johnson told a news conference.
Volunteers from many organizations - including professional trackers, searchers on horseback and the King County dive team - arrived early at Marymoor Park in Redmond. The 640-acre expanse on Lake Sammamish is one of the region's most popular parks, and as teams fanned out in hopes of finding 2-year-old Sky Metalwala, people went jogging, walked their dogs and played soccer games nearby.
Authorities had received no information leading them to the park, but were searching there merely because of its proximity to the apartment complex where the boy lived with his 4-year-old sister and their mother, Julia Biryukova, Johnson said.
Investigators also took another look Saturday at the area in Bellevue where Biryukova reported Sky missing last Sunday, claiming he vanished when she left him sleeping alone in her stalled, unlocked car for an hour while she walked to get gas. No further clues were immediately turned up there, either.
Asked what his instincts told him about Sky's fate, Bellevue Police Maj. Mike Johnson told a news conference, "I'd like to stay away from my gut instincts. We hope we can find Sky and hope we can do it quickly."
Investigators remained frustrated that Biryukova, who was in a nasty divorce and custody fight with Sky's father, refused to meet with them. They had previously asked her to take a lie-detector test, but her divorce lawyer said she was in no emotional condition to do so, and she has not responded to their invitation to speak with them voluntarily, Johnson said.
Biryukova, 30, did speak with police the day she reported the disappearance, accompanying investigators as they drove the route she said she walked from her stalled car to a gas station. But she remains a focus of the investigation because, police say, her story didn't add up. There turned out to be plenty of gas in the car, which was suffering from no apparent mechanical problems when detectives gave it a test-drive.
Sky's parents had reached a tentative agreement for visitation after a 12-hour mediation session last week. But Biryukova backed out of the agreement Friday, two days before she reported Sky missing.
The family has a previous record of leaving Sky alone in a car. Redmond police cited both parents for reckless endangerment in 2009 after they left him sleeping in their Cadillac sport-utility vehicle at a Target store parking lot for nearly an hour.
Johnson said police have no immediate plans to arrest Biryukova for reckless endangerment or other charges based on the story she gave about his disappearance. That's a strategic decision designed to encourage her cooperation, scant though it has been, he said.
A defense attorney representing Biryukova has not returned repeated calls or emails seeking comment.