At 9 a.m. Saturday, civilian teams will search the perimeter of the lake while professional divers go out on the water, said San Leandro business owner Sherri Miller, who is organizing the search.
Hasanni, who has cerebral palsy, was reported missing from the parking lot of the Shuz of Rockridge shoe store in the 6000 block of College Avenue in Oakland at about 4:15 p.m. on Aug. 10.
Police said they are now treating the case as a homicide, and Hasanni's foster parents - his 30-year-old aunt, Jennifer Campbell, and her boyfriend, 38-year-old Louis Ross - were arrested on murder charges but released due to insufficient evidence.
Miller said she hopes Saturday's search will provide new leads in the case. She and two colleagues came up with Lake Elizabeth because it's big, it's in Fremont and it hasn't been searched yet.
"It's a large area, and we have enough volunteers to search it," Miller said, adding that close to 100 people have signed up to help search the region.
"Lake Elizabeth is our meeting point, and we're branching off into teams tomorrow," Miller said. "We won't know until tomorrow where we're sending them."
Miller said San Jose Search and Rescue, a nonprofit that helps with missing person searches and other recovery operations, volunteered their entire team.
She said she also invited Alameda County law enforcement officials to participate, but the Fremont Police Department and the county sheriff's office declined.
Fremont police announced that a public information officer would not be available to discuss the decision, and the Alameda County sheriff's office could not be reached for comment.
Miller said she is still looking for food donations for the volunteers, and anyone who would like to help is asked to call: (510) 276-9090.