Grant Boyette, 18, and Justin Sledge, 16, were originally charged with murder conspiracy. Indictments Thursday charge each with two counts of accessory before the fact of murder, a crime punishable by life in prison.
The new charges came two days after prosecutors described Boyette as the ringleader of a group known as the ``Kroth'' which sought to destroy its enemies and practiced satanic worship.
For months, the small group of misfit teens allegedly plotted an elaborate plan to raid Pearl High School, and they chose member Luke Woodham as an assassin.
Woodham, 16, is charged with stabbing his mother to death in their home on Oct. 1, then going to school and gunning down two students -- including his former girlfriend -- and wounding seven. Woodham was being held without bail on three counts of murder, each of which carries a possible life sentence.
Four other teens were also charged last week with murder conspiracy and face up to 20 years if convicted.
The indictments Thursday claim that Boyette and Sledge met several times with Woodham to convince him ``that murder was a viable means of accomplishing the purposes and goals of the shared belief system.''
Investigator Greg Eklund testified in a court hearing this week that Woodham's former girlfriend, Christina Menefee, was targeted.
``On many, many occasions, (Boyette) told Luke Woodham that he should just kill her and be done with it so he won't have to see her again,'' Eklund said.
Menefee, 16, was the first person Woodham shot after taking a rifle into a crowded school commons before classes, authorities have said.
Also at the hearing, Rick Brown, a longtime friend of Boyette, said his pal was fascinated by the manipulation abilities of Adolf Hitler. Brown said he feared that Boyette, a freshman at a nearby community college, had an influence on the younger Woodham.
``Luke was a social recluse all his life. I thought he would be easy to control and easy to manipulate,'' Brown said.
In a five-page handwritten note police described as a manifesto, Woodham writes: ``throughout my life I was ridiculed. Always beaten, always hated. Can you, society, truly blame me for what I do?''
Woodham then crossed out the words ``No, you can't,'' and wrote, ``Yes, you will, the ratings wouldn't be high enough if you didn't, and it wouldn't make good gossip for all the old ladies.'' He finishes the page with ``Grant, see you in the holding cell!''
Authorities said they obtained the notebook paper sheets from Sledge. Before his arrest, Sledge said Woodham handed him the notes shortly before opening fire at the school. Sledge said the notes were intended for Boyette.
Assistant District Attorney Jim Kelly would not comment Thursday on the new charges or say if other indictments were expected.
Attorneys for Boyette and Sledge did not return phone calls Thursday.