The rhetorical device used by Mark Antony is paralipsis.
Paralipsis is a noun that in Rhetoric means the device of giving emphasis of a certain point by professing to say little or nothing about a subject.
Examples of paralipsis:
I know who is responsible but I won't say Jack's name.
(You are stating that Jack is responsible)
I don't want to talk about her unsavory reputation.
(You are implying that she has an unsavory reputation)
I know nothing about your unpaid debts to Marla.
(You are know about the unpaid debts)
