Red john is smart and sadist
through the series false leads to red john beeing male, which makes obvious assumptions the smart killer would disguise herself as the oposite gender
She is a mentalist, always close to jane, knows everything he knows at the same time hiding in sight, she has connections to every suspect also, and police intel.

Sadistically she subconsiously show herself as the killer to torture jane for her own pleasure
leaving hints that jane leave in the air, and acumulate pain
initials teresa lisbon , TL, Red John, RJ
the letters S and K are alphabetically aparting their initials, which stands for serial killer.
it is certain that teresa is redjohn, however, her motives remain a mistery for me, why Jane? Whar's the real motive for teresa to pick on Jane?