Karen Read who works with her defense lawyers attends a "side bar" conference with the prosecution and Judge Cannone during her retrial at Norfolk Superior Court, Wednesday May 28, 2025, in Dedham, Mass. (Greg Derr/The Patriot Ledger via AP, Pool) AP

Elizabeth Laposata is a clinical associate professor of pathology and laboratory medicine at Brown University's Warren Alpert School of Medicine. She is a graduate of Bucknell University and the University of Maryland who now resides in Providence.

But on cross-examination, defense attorney Robert Alessi pointed out Welcher was not the first crash expert to work with prosecutors on Read’s case. He name-dropped Massachusetts State Police Trooper Joseph Paul, who testified for the prosecution during Read’s first trial and appeared flustered under scathing questioning by the defense.

Karen Read pleaded not guilty to murder charges in the death of Boston police officer John O’Keefe and is facing a retrial after a jury was unable to reach a verdict last year.

The digital evidence in Karen Read's retrial, including John O'Keefe's last movements, is examined by Vinnie Politan.

The final witness for the prosecution in the Karen Read retrial is expected to wrap his testimony in Thursday's truncated session.

Dr. Judson Welcher said he believes the damage to Read’s SUV and relevant data was “consistent with a collision” with O’Keefe as long as the vehicle was moving faster than 8 miles per hour.

The prosecution in Karen Read’s murder retrial filed a motion on Wednesday asking Judge Beverly Cannone to remove a key piece of evidence from the court record.