Charges against a Bronx teenager accused of a fatal school stabbing were reduced from murder to manslaughter.

Abel Cedeno, 18, appeared before a grand jury Tuesday. 

He is accused of fatally stabbing 15-year-old Matthew McCree and critically injuring another classmate. 

Outside of the courthouse, advocates, supporters and family members united in a rally to support Cedeno.  His sister claims he was the target of bullying since the sixth grade.      

Cedeno is being held without bail.  He has pleaded not guilty to murder and manslaughter among other charges.