A school in the Flint school district saw a lockdown for a brief time yesterday following an emergency call about a person with a gun.  It is reported that a Flint school district spokesman stated the lockdown order at Northern High School was lifted around 9:55 a.m. Thursday after police searched the building and no weapons were found.  A 911 call had been received earlier Thursday morning claimed a person at Flint Northern was armed and making threats.  The school was notified by police and the safety plan was put into action.  Investigation continues