Karen Read's SUV reached '74% throttle' moments before John O'Keefe's final movements, crash expert testifies

The prosecution successful Karen Read’s trial looked to cement its communicative surrounding the decease of Boston Police Officer John O’Keefe by turning to a clang expert’s information placing Read astatine the transgression country during O’Keefe’s last movements connected the greeting of his death. 

Read, 45, is accused of hitting her boyfriend, 46-year-old O’Keefe, with her Lexus SUV successful a drunken rage successful the aboriginal greeting hours of Jan. 29, 2022, earlier leaving him to frost to decease successful the beforehand gait of a chap officer’s location successful Canton, Massachusetts.

On Tuesday, peculiar authoritative Hank Brennan called the state’s likely last witnesser to the stand. Dr. Judson Welcher, an mishap reconstructionist and biomechanical technologist with Aperture LLC, testified that the achromatic container information wrong Read’s conveyance did not registry a collision connected the greeting of O’Keefe’s death, but helium insisted the deficiency of information is expected due to the fact that the strategy lone registers car-to-car crashes, not pedestrians.

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Karen Read is shown during her execution proceedings astatine Norfolk Superior Court successful Dedham, Mass., connected May 27, 2025. (Matt Stone/Boston Herald via AP/Pool)

"Were you amazed that determination was nary accusation astir a collision successful the [black box]?" Brennan asked.

"No," Welcher said. "[It was] precisely what I expected." 

Welcher testified that helium was capable to lucifer Techstream information from Read’s Lexus SUV to the vehicle’s infotainment timepiece utilizing reports from his colleague, Shanon Burgess, showing the infinitesimal Read’s conveyance was turned on. 

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Evidence photos from Dr. Judson Welcher’s probe are shown during Karen Read’s proceedings connected May 27, 2025. (Pool)

"So we’re going from the moving timepiece to a real-world clock," Welcher said. "If you instrumentality erstwhile [the vehicle] was turned connected from Burgess’ report, you tin spot that the Lexus was turned connected astatine 12:12:36 a.m."

The Techstream timepiece wrong Read’s conveyance was 21 to 29 seconds down O’Keefe’s cellphone clock, requiring investigators to beforehand the information to lucifer the cellphone, Welcher explained.

"That’s wherefore you request to person an apples-to-apples comparison," Welcher said. "You request to get them connected the aforesaid clip clock."

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Dr. Judson Welcher testifies during the Karen Read execution proceedings connected May 27, 2025. (Matt Stone/Boston Herald via AP/Pool)

Approximately 19 minutes aft the ignition was turned on, Read’s conveyance registered a 2nd trigger event, according to Welcher. Pointing to revolutions per minute, acceleration and shifting information from the achromatic box, Welcher testified that Read’s conveyance drove guardant 34 feet earlier backing up 53 feet astatine a 74% throttle, with information indicating the car was traveling astatine 23 mph by the extremity of the trigger event.

Welcher pointed to information from O’Keefe’s phone, telling Brennan the accelerated acceleration of Read’s conveyance matched with the timestamp of O’Keefe’s last enactment with the device. 

"[The trigger event] matches the model of the cellphone information for O’Keefe," Welcher said. "That puts [the vehicle] successful beforehand of 34 Fairview." 

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Prosecutor Hank Brennan questions a witnesser during the Karen Read execution proceedings connected May 27, 2025. (Matt Stone/Boston Herald via AP/Pool)

The information corroboration further solidifies the prosecution’s timeline surrounding what allegedly caused O’Keefe’s decease extracurricular the Massachusetts home. 

"At champion for the defendant, this witnesser is moderately damaging," retired Massachusetts Superior Court Judge Jack Lu told Fox News Digital. "Seventy-four percent acceleration, nary brake; Welcher is likable and nonrecreational but not implicit the top, benignant of humble." 

Welcher turned his attraction to surveillance footage showing Read pulling retired of O’Keefe’s driveway soon earlier discovering his lifeless assemblage successful the snow, testifying that his probe concluded the bumper of Read’s conveyance did travel successful interaction with O’Keefe, but the taillight did not. 

"I hatred to spot immoderate enactment get hurt, but this was a atrocious time for Ms. Read," Lu said. "She [was] driving a precise high-end luxury Lexus SUV and pushed the throttle beyond 70% with nary braking. That Lexus SUV indispensable person taken disconnected similar a SpaceX rocket ship. That is the quality of the beast – a precise atrocious look for Ms. Read."

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Defense lawyer Robert Alessi confers with Superior Court Judge Beverly Cannone arsenic Karen Read, left, looks connected astatine Norfolk Superior Court successful Dedham, Mass., connected May 27, 2025. (Matt Stone/Boston Herald via AP/Pool)

"So the lone grounds of interaction is obscurity adjacent the precocious taillight," Welcher said. "I stress the connection ‘upper taillight’ due to the fact that it is close successful enactment with the little taillight, but yet the little taillight was besides not broken." 

The clang adept testified helium performed his ain experimentation with a conveyance that is the aforesaid marque and exemplary arsenic Read’s SUV to analyse the imaginable origin of scratch marks recovered connected O’Keefe’s arm. 

Upon learning helium was astir the aforesaid tallness and value arsenic O’Keefe, Welcher covered the taillight successful overgarment earlier reenacting a conveyance strike, with video footage indicating the overgarment near marks connected his limb successful the aforesaid country arsenic O’Keefe’s injuries. 

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"The determination predisposition of the laceration connected O’Keefe’s close forearm and limb are accordant with the geometry and predisposition of the close taillight of [Read’s SUV]," Welcher said. 

Welcher testified helium besides studied the quality of injuries sustained by assaults, telling Brennan his probe led him to reason that O’Keefe was struck by Read’s SUV. 

"Based connected each the grounds you considered," Brennan said, "could you stock with the assemblage what your sentiment is, to a tenable grade of engineering certainty, astir whether the defendant's Lexus struck Mr. O'Keefe connected Jan. 29, 2022, astir 12:32 a.m.?"

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"Based connected the totality of the evidence, DNA, everything I've talked about, that is accordant with that happening," Welcher said. "With a tenable grade of technological certainty, that is what happened."

Welcher’s grounds served to further solidify the information findings by Burgess and Cellebrite adept Ian Whiffin, who antecedently took the basal arsenic witnesses for the prosecution successful Read’s case. 

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The prosecution is expected to remainder its lawsuit this week aft an full time of Welcher’s nonstop examination. If convicted of the apical charge, second-degree murder, Read faces the anticipation of beingness successful prison.

"So far, without cross-examination, the defence is having a atrocious day," Lu said.