A Long Island elementary-school teacher obsessed with cannibalism and kids — who served six years in federal prison on child-porn charges — is missing.

Michael Kelly Reiner, 52, has apparently walked away from a work-release program and the strict probation that came with his release last year, according to court documents.

Reiner had been living in a Brooklyn halfway house since his May 2012 release.

kboniello@nypost.com