Authorities and volunteers are expanding their search efforts today for a 2-year-old boy from Washington who has been missing for a week.
Police said they are doubling back on their earlier work and retracing their steps to find Sky Metalwala.
Without any significant leads, police are growing doubtful they'll find the boy alive.
"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 said.
K-9 units have covered the ground, hoping to pick up the scent of the missing toddler as dive teams combed the waters, looking for any clues.
On Saturday, police scoured a park near the apartment complex where Sky lived with his mother, Julia Biryukova.
Biryukova told police earlier that she left Sky alone in her car after she ran out of gas and walked off for help. When she returned to her silver Acura SUV, the child was gone, she told police.
According to police, Biryukova did walk to the Northtowne Chevron Service from where she left her SUV, but she never bought gas there, police said.
Instead, she spent time walking around a wealthy neighborhood where she reportedly didn't ask anyone for help, officials said.
When detectives checked to see how much gas was left in her car, they found enough for her to have continued driving.
Investigators took her car for a test drive, to see if it had any mechanical problems that would have forced her to leave it on the side of the road.
Police said they are now convinced it didn't have engine trouble and there was plenty of gas in the tank.
"I'll let the evidence speak to itself, which is there was gas in the car and was able to drive and operate. That's not what Julia told us," Johnson said.
Police said that after Biryukova visited the gas station she called a friend who picked her up and took her back to her two-door silver Acura, where they allegedly discovered the boy was missing.
Sky's father, Solomon Metalwala, said Wednesday that he thinks Biryukova is connected with his son's disappearance.
"I do believe that Julia has a, she's responsible …," Metalwala said speaking of Biryukova. "It's sad. Because if she can just cooperate, we can find where, where is our son."
Metalwala has agreed to take two polygraph tests, but Biryukova has refused to be tested, telling investigators that she has been too disturbed to participate.
Police have made a public appeal for Biryukova's cooperation, and have also asked the public to help.
Biryukova's attorney declined requests for comment to ABC News.