Trial of Matthew Farwell, accused of killing Sandra Birchmore, continues

• Matthew Farwell, a former Stoughton police officer, is on trial for the alleged murder of Sandra Birchmore.
• Farwell faces federal charges including killing a witness or victim and killing a child in utero.
• Testimony includes evidence from Birchmore's apartment and cross-examination of a homicide investigator.
• Federal prosecutors seek to admit testimony about Farwell's alleged extramarital affairs.
• The trial involves the presentation of photos, video, and expert testimony from a toxicologist.