The high-profile Karen Read trial is back in Norfolk Superior Court in Dedham, Massachusetts on Thursday for a 16th day of witness testimony. The day began with a Massachusetts State Police forensic scientist back on the stand for cross-examination about evidence processing.

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.

Canton Fire Department paramedic Timothy Nuttall shows how to do a Carotid Pulse at Karen Read's second murder trial at Norfolk Superior Court on Tuesday, April 22, 2025 in Dedham, Mass. Photo by Stuart Cahill/The Boston Herald via AP, Pool

What happens if prosecutors don’t call key witnesses in Karen Read retrial? 03:40. After three full days of testimony from Massachusetts State Police Sgt. Yuri Bukhenik, lawyers

Several new attorneys, Karen Read’s media interviews and the firing of the lead investigator have combined to change the dynamics of her retrial.

The case out of Dedham, Massachusetts, has turned into a yearslong whodunnit legal saga that has captivated true-crime fans across the country.

Prosecutors argue that flirty text messages presented to the jury last week opened the door to testimony about what happened during the vacation about one month before John O'Keefe's death.