This might have been worth mentioning three weeks ago.

A juror who declared — after the first day of a vehicular manslaughter case — that she would not “send a black man to jail,” caused a mistrial Thursday in the case of an African-American man who crashed his car into a young art curator​, killing her.

A fellow juror said she overheard Juror No. 3 mutter, “I won’t send a black man to jail, that’s crazy,” as she left court after the first day of father-of-six Marlon Sewell’s trial in Brooklyn, which started on Sept. 11.

But Juror 8 didn’t say anything until Thursday — three weeks in and after three full days of deliberations that got so heated because of the biased juror’s obstinateness that she fainted in the jury room a day earlier — because she thought the middle-aged woman would ultimately change her stance and keep a fair and open mind.

Juror 8 — who told reporters that she and another panelist heard the utterance — as well as Juror 3 and Sewell are all black.

The runaway juror refused to answer questions as she left court Thursday,​ hissing to reporters, “​G​et away from me.”​​​

Other jurors, who also declined to give their names, said they’d been leaning toward a conviction — but Juror 3 “had her mind made up, and wasn’t open to hearing anything else.”

Even the judge was blown away by the intractable juror.

“I’ve never seen a note like this,” Brooklyn Supreme Court Judge Vincent DelGiudice said Thursday before he dismissed the jurors. “Where one juror is racially biased in favor of the defendant.”

Juror 3 apparently caused so much turmoil that on Wednesday, Juror 8 had to be hospitalized after tensions boiled over​. She suffered a panic attack and an ambulance was called because she felt she was being “persecuted” by the rogue juror.

“This person was just creating so much conflict in this room,” Juror 8 said after the panel was released. “I couldn’t take it, I fainted. And started trembling and crying.”

Luckily, she was caught by another juror as she collapsed.

Sewell, who was driving with a suspended license at the time of the fatal crash, will be retried on manslaughter charges Nov. 12. He faces up to 15 years behind bars if convicted for his role in the 2015 crash that left Victoria Nicodemus dead, and others injured.

“This was a tragic accident,” defense lawyer Damien Brown said of Sewell’s case as he left the courtroom. “This could have happened to anyone, it could have been you or me walking down the street. I don’t think he’ll ever drive again.”

Prosecutors allege Sewell ignored a gas leak in his car that caused him to jump the curb and slam into a group of holiday shoppers. Sewell maintains there is no evidence of a leak.