(CNN) -- The search continued Monday in suburban Seattle for a 2-year-old boy who police said went missing after being left alone in a car by his mother the previous day.
The Bellevue (Washington) Police Department acknowledged Monday, in a statement, that "there are still many unanswered questions." It said that no arrests have been made and both parents of the child, named Sky Metalwala, are cooperating.
"We have received consent from the mother to search the vehicle and also her home in Redmond," police spokeswoman Carla Iafrate told reporters Monday. "We're currently searching the area around her home in Redmond with several officers out there and FBI agents."
According to police, the boy's mother said she ran out of gas in Bellevue, which is just east of Seattle, leaving the toddler in the car while she took her 4-year-old with her to get help.
The mother said the young boy was gone when she returned to the vehicle, about an hour later, police said.
Sky has brown eyes and dark, closely cut hair, and was wearing a dark green hooded sweatshirt and blue-and-gray striped pants when he was last seen.
Authorities placed automated calls to people in the area after the boy was reported missing, urging people to call 911 if they spotted him.
King County Search and Rescue began looking for the child before suspending their ground search Sunday evening, according to a post on the Bellevue Police Department's Facebook page.
The investigation resumed Monday, including a search around where the child lived in Redmond, which is to the northeast of Bellevue. The law enforcement agencies involved include the FBI, King County Search and Rescue, King County Guardian One Helicopter and Redmond and Bellevue police departments.
"All possibilities of what might have happened to the child are being investigated," Bellevue police said in their statement Monday.