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 prosecution is resting its case in Karen Read’s second murder trial after a battery of witnesses and presentation of new evidence.

Karen Read's defense attorneys cross-examine key accident expert Judson Welcher in a dizzying day of testimony.

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.

Judson Welcher, a crash reconstructionist called by the prosecution, is back on the stand for a second day of testimony in the Karen Read trial.

A crash reconstruction expert who on Tuesday provided jurors his analysis of Karen Read’s vehicle the night her Boston police officer boyfriend was killed is expected back on the stand.