This article doesn't mention the FBI agent's motive either. Nor does it provide any evidence that this is a political attack; it's not like you can impute that

This article doesn't mention the FBI agent's motive either. Nor does it provide any evidence that this is a political attack; it's not like you can impute that solely from the fact that the target has a political stance. It is a better article, if you can ignore the hyperbolic spin, in that it links to more information -- the fact this was known at the original trial, and the appeals court being quoted, "the evidence the agent destroyed lacked exculpatory value and the information was available by other means".