"He would be empowered by Allah to carry out this mission," Cornell said Malvo was told.
It included Muhammad converting Malvo to his form of Islam and offering a mental diet of racial injustice.
"He introduced him to the Willie Lynch speech," supposedly delivered in 1712 by a slave-owner who traveled to Virginia to tell slaveholders how to control their African chattel by setting them against each other. However, historians disagree over whether the speech is fact or folklore, Cornell said.
"He used it as proof there was a conspiracy of white people against black people," the psychologist said.
"Allah favors the black people, and at some point is going to assist or call for an uprising, a holy war" against white oppressors, Cornell said Malvo told him.
Malvo was unusually vulnerable because he had been chronically uprooted and beaten as a child by his mother, bullied by kids at school and not allowed to form healthy bonds with adults, the psychologist said.
Cornell diagnosed the youth as suffering from a dissociative disorder, a mental illness that would take years of therapy to overcome.
Sun staff writer Stephen Kiehl contributed to this article.