Karen Read investigator who sent vulgar texts about her case ...

The Massachusetts state trooper accused of manipulating evidence in the case of Boston officer John O’Keefe's death and sending vulgar texts about Karen Read, O'Keefe's girlfriend and the prime suspect in his death, was relieved of duty Monday after a judge declared a mistrial in the case.

Colonel John E. Mawn, Jr. said in a statement late Monday that Massachusetts State Police "took immediate action to relieve" Trooper Michael Proctor.

State police had opened an internal affairs investigation into Proctor, the lead investigator in the death of O'Keefe, after Read's defense team alleged at her trial that he failed to properly investigate the Jan. 29, 2022 death, manipulated evidence and made derogatory comments about Read, who was accused of backing her SUV into her police officer boyfriend and leaving him to die outside.

Massachusetts State Police Trooper Michael Proctor, right, takes the stand to testify, on June 10, in Norfolk Super Court, in Dedham, Mass., during the trial for Karen Read.Kayla Bartkowski / The Boston Globe via AP, Pool

"Our focus remains on delivering the highest level of police services with professionalism and integrity. The Department has relieved Trooper Proctor of duty effective immediately," Mawn said in a statement, noting that the internal affairs investigation continues.

Proctor will also be transferred out of the detective unit assigned to the Norfolk County District Attorney’s Office effective Sunday, the colonel said.

Mawn also offered condolences to O’Keefe's family.

"We cannot imagine the way in which this result has heightened the O’Keefe family’s immeasurable grief, heartache, and sense of loss," he said. "John lived a life of honorable service — both to the City of Boston and the children entrusted to his care after the unexpected death of his sister and brother-in-law. We will remember him."

O’Keefe, 46, was found unresponsive outside the home of another Boston officer, Brian Albert, who was having a gathering in Canton, a Boston suburb. He was later pronounced dead, and a medical examiner attributed his death to blunt force trauma to the head and hypothermia.

Karen Read at Norfolk Superior Court in Dedham, Mass., on June 28.Charles Krupa / Pool via AP

Prosecutors argued that O'Keefe and Read, an equity analyst at Fidelity Investments, had a tumultuous relationship that culminated with her backing her Lexus SUV into him and leaving him for dead. She was charged with second-degree murder, vehicular manslaughter and other crimes.

Read’s lawyers, however, said that O’Keefe appeared to have been ambushed, beaten, and bitten by a dog at an afterparty at the home. He was then left outside, the defense said, alleging that Read was framed for a murder she did not commit.

Her lawyers also said Proctor's investigation was biased and accused him of failing to pursue other potential suspects and not disclosing his relationships with the Albert family. Proctor's sister was close friends with Albert’s sister-in-law, and he worked on a cold case and was friends with Albert’s brother, Read's defense team said.

Proctor testified that he referred to Read using derogatory language in text messages with other troopers.

In one message, Proctor used an offensive term for developmentally disabled people while describing Read and told other troopers that he hadn’t found any nude photos of Read while searching her cell phone. He also acknowledged sending a text to his sister days after O’Keefe's death saying he hoped Read took her own life.

Proctor told the courtroom that his comments "dehumanized" Read and were unprofessional, but didn’t compromise the integrity of the investigation.

Read’s attorneys, David Yannetti and Alan Jackson, released a joint statement after Proctor was relieved of duty, saying "conduct has consequences."

"DA (Michael) Morrissey backed this misogynist corrupt cop, and 2 hours after he announced he will pursue a second trial against an innocent woman Karen Read, The Massachusetts State Police announced that Michael Proctor the lead investigator for the Commonwealth has been relieved of duty ‘because of serious misconduct that emerged in testimony at the trial," they said in a statement to NBC Boston. "We look forward to another opportunity to reveal the truth about this unjust prosecution. Good Luck."