Karen Read’s retrial in the death of her Boston police officer boyfriend John O’Keefe kicked off Tuesday with expected fireworks almost immediately – and they continued after Judge Beverly Cannone sent jurors home for the day with a heated hearing on late discovery disclosures.

Both sides painted entirely different versions of events as they delivered their opening statements to the jury, but after the panel left for the day, Cannone called for a new hearing Friday and accused the defense of violating one of her orders on reciprocal discovery.

Defense attorney Alan Jackson opened with a challenge to the heart of the prosecution’s case: that O’Keefe died from injuries sustained when Read’s Lexus SUV allegedly struck him during a nor’easter.

“The evidence in this case will establish, above everything else, three points,” he said. “There was no collision with John O’Keefe. There was no collision. There was no collision.”

KAREN READ DEFENSE FACES ‘HIGH-WIRE’ ACT AS RETRIAL’S OPENING STATEMENTS KICK OFF, EXPERTS SAY

Special prosecutor Hank Brennan told a different story in his own opening statement, minutes earlier, saying to jurors that Read, allegedly drunk and angry, intentionally hit the gas and rammed O’Keefe with the back bumper, then left him on the ground, where he was later found with severe head injuries and hypothermia.

Both cases may hinge on whether a pair of defense experts are allowed to testify about their conclusions.

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After jurors left, the sides argued in a heated motion hearing about whether expert testimony from the ARCCA crash-reconstruction firm should be allowed. 

Two experts from the firm testified during the first trial, disputing the prosecution’s version of events.

Brennan told the judge that prosecutors have become aware of additional conclusions from the experts – new information that his team would not have time to adequately prepare for because disclosures have not been made.

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Defense attorney Robert Alessi said it was Brennan’s team that caused delays in discovery by revising its own expert disclosures in March, with just weeks to go before Read’s retrial kicked off with jury selection on April 1.

“At a prior hearing, I found a violation of the defense’s reciprocal discovery obligations,” Cannone said. “It was clear to me, and I found that it was deliberate. This appears to me contrary to what you’ve argued, Mr. Alessi, that this is another violation of my order and of the reciprocal discovery violations. We need to figure all of this out before you’re allowed to call these witnesses.”

To accomplish that, she ordered a voir dire hearing with the ARCCA experts Friday morning. Jurors will not be present all day.

Grace Edwards, an Essex County trial attorney who has been following the case, said the end-of-day hearing left her floored.

“They still don’t have the sallyport video,” she said, referring to Read’s defense and police surveillance footage from the day her SUV was first impounded. “They played hide the video. This feels harsh.”

Brennan had previously asked Cannone to exclude the ARCCA team, and Edwards predicted that whatever new testimony ARCCA is expected to bring could be problematic for the commonwealth.

“She barely allowed this to begin with. She can’t be happy about this,” said Paul Mauro, a former NYPD inspector who has been following the case. “Very bad news for the defense.”

KAREN READ DEFENSE FACES ‘HIGH-WIRE’ ACT AS RETRIAL’S OPENING STATEMENTS KICK OFF, EXPERTS SAY

Read appeared to disagree, smiling when she met reporters outside on courthouse steps.

“I feel great,” she said. “Today went well. We prepped hard, and I’m just proud of my team.”

When asked why Jackson didn’t start his opening statement like fellow defense counsel David Yannetti did last year, telling jurors she had been “framed,” she replied, “We don’t like reruns.”

First to take the stand was Commonwealth’s witness Timothy Nuttall, a paramedic who checked O’Keefe when an ambulance arrived at the scene around 6 a.m on Jan. 29, 2022. 

He testified that while first responders were attempting to give O’Keefe CPR, Read said, “I hit him. I hit him. I hit him.”

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But on cross-examination, Jackson was quick to call Nuttall’s memory into question, noting that during Read’s first trial last year, he testified that Read said the phrase only twice. 

He also confronted Nuttall with his own testimony about what O’Keefe was wearing – which turned out to be wrong when he testified about it last year. Then he replayed dashcam video of paramedics on the scene, asking him to walk through it and pointing out where his testimony did not line up with what was on the screen.

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Nuttall appeared uncomfortable at times, as Jackson questioned his memory, his prior testimony, and his timeline of events repeatedly. But he insisted that he heard Read say “I hit him,” repeatedly.

The second witness was Kerry Roberts, a friend of O’Keefe’s whose son was the same age as his adopted nephew. Although she grew up with the victim, she said they became closer after he adopted his sister’s orphaned children following a family tragedy.

Roberts was one of the people Read called on the morning of O’Keefe’s death.

She said she was driving Read and Jennifer McCabe as they looked for him that morning. After first searching his house and coming up empty, they went to the Albert home – where McCabe and other friends and acquaintances had gone for an after-party the night before.

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“As we approached the house, Karen from the back seat is now screaming, ‘There he is! There he is! Let me the F out of this car,’ kicking the back door to get out,” Roberts testified.

Visibility was poor, she said, and she couldn’t see O’Keefe until Read went up to a body-sized “mound” on the front lawn.

Judge Cannone sent jurors home for the day after that testimony. Roberts is expected to return to the stand Wednesday morning.

The trial is expected to last six to eight weeks after taking more than two weeks to seat a jury.

Read could face a maximum of life in prison if convicted of the top charge, second-degree murder.