McNamara told jurors she met Farwell when he was a child in the department’s Police Explorers program. He began working with the program before becoming a police officer, she said. Farwell is accused of beginning a sexual relationship with Birchmore when she was 15 and participating in the program. McNamara said she ended the program in late 2022.

Birchmore died in 2021, and her death was initially ruled a suicide. Federal prosecutors allege Farwell strangled her and staged the scene, and that he killed her and her unborn child to silence her over allegations of sexual exploitation. Farwell has pleaded not guilty.

McNamara’s testimony follows an internal investigation she ordered into Birchmore’s death and her interactions with Stoughton police. The investigation found that three department members, including Farwell, had inappropriate sexual relationships with Birchmore. At a 2022 news conference, McNamara said the conduct violated department policies and values.

The case has also become part of a bitter dispute in Stoughton. McNamara is on paid administrative leave amid a conflict involving Town Manager Thomas Calter, who is also on leave. McNamara sued Calter and the town, saying there was no lawful reason to prevent her from working as chief. An independent investigation led by former Boston Police Commissioner Ed Davis is examining allegations involving the chief and harassment claims she has made against the town manager.

Calter said in an August statement that he did not ask McNamara to interfere with any investigation or report concerning Birchmore. McNamara’s leave and the dispute have prompted public demonstrations and calls from residents for changes in town leadership.