The Bellevue Police Department says it has existed all leads in its search for Sky Metalwala, a 2-year-old boy who went missing in the city Nov. 6, 2011, though detectives remain hopeful he may one day be found.

Police have received 2,200 tips and leads in the two years since Metalwala’s disappearance, all of which were investigated when they came in to the police department, according to a news release. With the impending anniversary of the child’s disappearance, investigators say they are frustrated none of the leads have led to finding the young boy, who would now be 4 years old.The investigation continues as a joint effort of the Bellevue and Redmond police departments.

Metalwala was in the care of his mother, Redmond resident Julia Biryukova, when he disappeared. The boy’s father has accused the mother of possibly turning over Metalwala to a friend or family member while they were in the process of divorcing at the time of his disappearance, however, Biryukova has yet to be formally interviewed by law enforcement.