About 75 volunteers, including off-duty officers, Boise State University officers and residents, methodically scoured the neighborhood around Robert Manwill's home Sunday.
A pond in his apartment complex, which had been searched by divers, was drained in the evening to make sure Robert wasn't in it, a police spokesman said.
The 8-year-old went missing 9:30 p.m. Friday from the 2800 block of Cherry Lane, near Vista Avenue and Targee Street in Southwest Boise. The New York Canal is about two blocks south of the apartment complex where Robert lives.
Boise police filed paperwork to issue an Amber Alert immediately but were denied because the incident does not meet the national criteria, said police spokesman Chuck McClure.
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Family members were the last to see Robert. Police at this point don't suspect any family member is involved in his disappearance.
Officers have been searching for him Friday night and have asked anyone who may have seen the boy, even for a moment walking down the street, to call them at Crime Stoppers, 343-COPS.
Robert is roughly 4 foot 2 inches tall, about 50 pounds. He was last seen wearing blue jeans, black shoes and a either a blue shirt with the Superman or Spiderman symbol on it, or a brown shirt that had the words "Andy don't need no mic" on it.