Long Branch police tell the Asbury Park Press (http://on.app.com/SHMw7m ) the boy died early Wednesday afternoon, one day after the accident.
The boy, identified only as an Ocean Township resident, was building the tunnel with his younger brother when it collapsed around 3:20 p.m. Tuesday.
The boy's mother was nearby when the collapse occurred and called 911. Emergency responders dug out the unconscious child and performed CPR on him.
Information from: Asbury Park Press, http://www.app.com