Karen Read’s defense saved her strongest witness for last, experts tell Fox News Digital, bringing in Dr. Andrew Rentschler to try to debunk the prosecution’s claims about how her boyfriend, Boston cop John O’Keefe, died.

Jurors have the day off Thursday and will begin deliberations after receiving instructions from the judge and listening to closing arguments Friday.

Read, 45, is accused of hitting O’Keefe, 46, with her 2021 Lexus LX 570 SUV on Jan. 29, 2022, and leaving him to die on the ground with a skull fracture during a blizzard.

Officer John O’Keefe poses for his official headshot. O’Keefe’s girlfriend, Karen Reed, is currently on trial for murder after he was found dead outside of a Massachusetts home in January 2022. (Boston Police Department)

Welcher drew the opposite conclusion from Rentschler – testifying that in his opinion, Read’s SUV clipped O’Keefe with a glancing blow, knocking him off-balance before he fell and cracked his skull.

“The defense could not have finished the trial any stronger than they did,” Bederow said.

Jack Lu, a retired Massachusetts judge and Boston College law professor, said having Rentschler go last was both a standard strategy and a good one.

Karen Read sits with her attorneys David Yannetti and Robert Alessi as they listen to prosecutor Hank Brennan during her retrial, Tuesday, June 10, 2025, in Dedham, Mass. (Matt Stone/The Boston Herald via AP, Pool)

“What stood out is that he was steadfast that Dr. Welcher’s testimony about simulating the contact was fallacious. Counterpoint: so was Rentschler’s,” Lu told Fox News Digital.

He said both are part of a profit-based consulting industry and at points, their testing came across as absurd.

“You have a disembodied arm hitting a Lexus, versus a grease-painted expert getting hit at low speed by a Lexus,” he said.

Cannone gave jurors the day off Thursday so the sides can hold a charging conference. The panel returns Friday for jury instructions and closing arguments.