Judge Beverly Cannone ruled Karen Read can't name one particular witness as part of a third-party culprit defense during her retrial.

More than three years after John O’Keefe’s snow-covered body was found outside a Canton home, Karen Read will face a jury once again.

Karen Read’s lawyers can try to argue ‘third-party culprit defense’ involving Brian Albert, Brian Higgins: Judge Beverly Cannone rules

Read’s defense has claimed all three were involved in a fight with O’Keefe where he sustained fatal injuries. While the defense will be able to develop their theory, Cannone ruled they cannot include it in their opening statement.

The retired agent would have testified that the police investigation into John O'Keefe's death "was not reliable," the judge wrote.

Judge Beverly Cannone ruled Monday that Karen Read’s defense team will not be allowed to blame others for John O’Keefe’s death by name during opening statements.

Nine law students from Boston-area schools are volunteering for Karen Read’s defense team, including five from Boston College, three from Harvard University and one from Northeastern University.

On the eve of the Karen Read retrial, Judge Beverly Cannone handed down rulings related to jurors and a defense expert for the heavily scrutinized Canton murder case.