A hearing on whether a defense expert will be allowed to testify in the Karen Read case resumes today in Dedham. 

Prosecutors want a judge to block Dr. Marie Russell from testifying that injuries to Boston cop John O'Keefe's arm were caused by an animal attack.  Prosecutors claim the arm injuries were actually caused by Read's SUV striking her boyfriend and causing his death in Canton in January of 2022. 

The hearing began last month and was continued until today after running long.  Russell did testify in Read's first trial, which ended in a mistrial last July.