The Manhattan district attorney’s office will halt the prosecution of Tracy McCarter, a woman charged with murder in 2020 after her estranged husband died in a confrontation with her, according to a letter sent to the judge presiding over the case.

Ms. McCarter’s lawyers have maintained that she did not stab her husband, James Murray, but that minutes after he choked her, she held a knife in a defensive posture and he charged. Her case has become a cause célèbre for activists seeking to draw attention to the perils of domestic violence.

The Manhattan district attorney, Alvin L. Bragg, had tweeted in support of Ms. McCarter while he was running for the office But activists were furious when, upon being sworn in, he continued with the prosecution.

In Friday’s letter to the State Supreme Court judge, Diane Keisel, which was shared with The New York Times by Ms. McCarter’s defense team, Mr. Bragg said that he could not allow the case to go forward. He wrote that he could not in good conscience “allow a prosecution to proceed to trial and ask a jury to reach a conclusion that I have not reached myself.”

Mr. Bragg “righted a grievous injustice,” said Sean Hecker, a lawyer for Ms. McCarter, in a statement.

“Tracy McCarter is an innocent survivor of domestic violence who has suffered mightily from a criminal justice system that demands change,” he said.

A spokeswoman for the district attorney’s office declined to comment, other than to say the next court appearance in Ms. McCarter’s case is Nov. 28.