According to an online fundraising drive apparently organised by the family of Myles Cosgrove, it is no longer safe for the Louisville officer to remain in his job.
It said his relatives were trying to raise enough money for him to stand down from the force, and take care of his family.
“The family of Detective Myles Cosgrove, an officer involved in the tragic Breonna Taylor case, is starting this fund in order to help secure the safety of Myles and his immediate family going forward,” says a posting on the website GiveSendGo.
“It has recently become clear that it will be impossible for Myles to safely return to his position serving the community with the Louisville Metro Police Department.”
It added: “We hope to raise enough funds to help him purchase the remainder of his service time, or “air-time”, so that he can retire from the LMPD and continue to focus on the safety of his family, a family that has been put continually at-risk over the past few months.”
Mr Cosgrove was one of three officers who fired shots into the home of the 26-year-old black medical worker when they conducted a “no knock warrant” operation at her home, as they sought to question a former boyfriend in March. The young woman was killed, her death leading to protests across the country that have demanded justice for her, and numerous other unarmed people of colour killed by the police.
The Courier-Journal, which was first to report the development, said a ballistics test by the FBI had indicated shots fired by Mr Cosgrove struck Taylor near her heart and likely proved fatal.
Last week, a grand jury failed to bring charges against any of the three officers involved in the incident for firing shots into Taylor’s home.
It ruled that Mr Cosgrove and Jonathan Mattingly were justified in their use of force. A third officer, Brett Hankison, was charged with three counts of wanton endangerment, for firing shots into a home next to Taylor’s.
Louisville police update on shooting at Breonna Taylor protest
Ben Crump, a lawyer for Taylor’s family, denounced the decision as “outrageous and offensive”.
Under Kentucky law, someone is guilty of wanton endangerment if they commit an act that shows “an extreme indifference to the value of human life”.
The newspaper said that Mr Myles’ family did not immediately respond to questions about the fund-raising drive, which by Monday afternoon stood at a little under $5,000.
The post said the family was going to raise $75,000 for Mr Cosgrove and his immediate relatives, who had “received countless threats”.
“Myles’ reputation has been completely dismantled and the psychological trauma is something that he will have to cope with for the rest of his life,” it said.
“Every day, the threats seem more legitimate and scarier; his family has been doxed and harassed, while the threats remain unrelenting. Although Myles may never feel completely safe again, if you can help us reach our goal, we can at least get him on a path to security and allow him to focus on his main objective: the safety of his family.”
Additional reporting by the Associated Press