While necromancy was practiced, rarely, in parts of the Roman empire, there is no evidence of it being practiced in Jewish regions, and it is several times more unlikely still that it was practiced in Jerusalem.
• Craig Keener: “…our evidence for the theft of corpses appears in Gentile regions, never around Jerusalem.” [The Historical Jesus of the Gospels (Wm. B. Eerdmans, 2009), 341.]
Even if Necromancers had some desire to use Jesus's body for their witchraft, they would not choose to steal it.
• …Necromancers would rather perform their ritual on site.1
• …in general, people wouldn't want to steal Jesus's corpse.
• …Jesus's crucified body would have been deemed valuable by Necromancers.2
• J.P. Holding (Apologist, researcher [specializes in New Testament studies]): “…all the evidence suggests that when necromancers had need of a body for their arts, they did not steal the whole body from the tomb. Instead, they would either conduct their rituals in the tomb itself, leaving the body where it was when they were finished; or, they would slice off whatever they needed mutilating the body and taking the selected parts with them, leaving the rest behind. It does not help critics to argue that Jesus' nose and ears may have been missing, while the rest of the body was still in the tomb!” [Defending the Resurrection (Xulon, 2010), 391.]