A dispatcher testified he was told to “never talk about this again” when he relayed a call from a woman claiming married Massachusetts cop Matthew Farwell was having an affair with her friend, Sandra Birchmore, according to a report.

Stoughton police dispatcher James Fitton told jurors that Farwell — who is on trial for allegedly murdering Birchmore — became irate and started cursing when Fitton tracked Farwell down to tell him about the call from that day, on Jan. 20, 2021, according to a report by the Boston Globe.

“He got visibly and audibly upset with me,” Fitton testified Tuesday.

“His facial expression changed to anger and he told me — including expletives — to never talk about this again.”

Fitton’s supervisor also told him to “forget about” the report, he testified.

Farwell later texted Fitton that night, saying the tipster and Birchmore were both “f–king insane,” he testified.

Fitton relented and agreed to not bring it up again, he told the jurors at the federal trial in Boston.

Prosecutors alleged that this call was the catalyst that prompted Farwell to decide to kill Birchmore just 13 days later, to keep her quiet about their affair and the fact he’d sexually assaulted Birchmore beginning when she was 15.

Farwell, 41, who resigned from the Stoughon police, allegedly strangled a pregnant Birchmore, 23, in her Canton apartment on Feb. 1, 2021, and staged the scene to make it look like she killed herself.

The murder allegedly occurred the day before Farwell’s wife had their third child, prosecutors alleged.

Birchmore was jealous of Farwell’s wife and demanded he have a child with Birchmore or she would expose their years-long entanglement to his wife, prosecutors alleged.

So Farwell begrudgingly agreed and Birchmore became pregnant with a son just a few months before her death in December 2020, the feds alleged.

They both believed Farwell was the father, but DNA testing after the death of Birchmore and her fetus disproved that belief, prosecutors claimed.

Farwell and Birchmore first met years earlier when Birchmore, then an aspiring cop, was in the Stoughton police’s “Explorers” program for kids which Farwell helped run. He allegedly groomed her for a year before he began sexually assaulting her when she was just 15. The legal age of consent in Massachusetts is 16.

Farwell has pleaded not guilty to charges of killing a victim or witness and causing the death of an unborn child. His lawyers claimed Birchmore committed suicide and used her alleged past struggles with mental health to bolster their defense.