James Clinton, 18, remained unconscious and in critical condition at an Anchorage hospital, the Anchorage Daily News reported Thursday.
Police said they were alerted to the teenager's presence in the home by a typed noted slipped under the door of the University of Alaska police department Monday night.
University police contacted Anchorage police, who found Clinton in the basement of the home.
"The note writer said they couldn't live with themselves having this kind of information and not saying anything," said police spokeswoman Jennifer Castro.
The residence, owned by Covenant House Alaska, was scheduled to be torn down Thursday so a parking lot can be built on the property, said Alison Kear, executive director of the non-profit organization that offers help to the homeless.
The public is being asked to help provide information about who beat Clinton and why, said police spokeswoman Anita Shell, KSKA-FM, Anchorage, reported.
Shell said Clinton may have ties to the Matanuska-Susitna Valley north of Anchorage and had several nicknames.
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