Karen Read is charged with second-degree murder, manslaughter and leaving the scene of a crime in the death of John O'Keefe.

Karen Read’s defense is set to call its first witness on Friday, marking a new phase in her retrial in the killing of John O’Keefe, her off-duty Boston police officer boyfriend whose body was found buried in the snow outside a home in Canton,

During his testimony, Matthew DiSogra said “none of” Read’s SUV techstream events “were triggered by a collision.”

The first witness called by Karen Read's defense explained that there were few scenarios where John O'Keefe's phone locked before Read's car accelerated in reverse.