Jury selection is underway in federal court for the trial of former Stoughton police detective Matthew Farrell.  He's accused of sexually exploiting Sarah Birchmore when she was an underage teenager and then killing the 23-year-old pregnant woman.   

Birchmore's death in her Canton apartment in 2021, was initially ruled a suicide until federal prosecutors got involved. 

The presiding judge reportedly told lawyers they should be prepared for opening statements as soon as this Friday.