The defense's sole stance is that Karen Read never hit the victim. Pre-trial they offered up three possible perps. Brian Higgins, Brian Albert, and Colin Albert. They do not have to prove any of them killed him, only that it's possible, more possible than Read killing him with her car. But the judge isn't allowing a full third party defense, which is why the defense cannot directly reference the FBI or the FBI's investigation. "During the hearing in which Mr. Lally was not present..." is as far as they can go.