Carnel Chamberlain disappeared last Thursday while in the care of his mother's boyfriend.
Saginaw Chippewa Indian Tribe spokesman Frank Cloutier says a search warrant to collect physical evidence was executed Monday. He says the warrant was related to the mother's boyfriend, but did not offer further details.
Carnel's mother says her boyfriend was caring for the boy at her home near Mount Pleasant while she was at work. The tribe said the boyfriend initially wasn't cooperative.
Cloutier says tribal police also have secured Carnel's home to preserve any possible evidence.
The tribe says Tuesday's search for Carnel is focused on a wooded area near a wastewater treatment plant.
