Kaichen 's former landlord , Carol Halperin of Chappaqua , said Kaichen claimed to have volunteered at Ground Zero in the aftermath of the attack .
Kaichen 's former landlord , Carol Halperin of Chappaqua , said Kaichen told her she volunteered at Ground Zero after the attack .
a database that represents data as a collection of tables in which all data relationships are represented by common values in related tables