This fact alone taints the entire investigation. Since when does the FBI outsource a criminal investigation to someone paid by one of the parties being investigated.
Outsource a criminal investigation, which could implicate members of the DNC.
Implicate them in a fraudulent scheme to rig a federal election (the primary).
Implicate them in a murder of the head of their IT department, Seth “Panda” Rich.
ICBW, but I think it was the DNC and NOT the FBI that had CrowdStrike examine the servers. The DNC refused to hand them to the FBI.