Lindsay Clancy’s defense. Luigi Mangione’s bombshell courtroom confession. Plus, ghost guns.

In Massachusetts, Lindsay Clancy is on trial for allegedly murdering her three children. Her family and former colleagues testify for the defense. In New York, Luigi Mangione pleads guilty to federal stalking charges in the killing of UnitedHealthcare CEO Brian Thompson, while his lawyers seek to have the state murder case dismissed. In Dateline Round Up, Alex Murdaugh appears for a preliminary hearing ahead of his retrial for the murders of his wife and son. Plus, the trial begins for one of three people accused in the ambush murder of 33-year-old father Jared Bridegan. And an expert explains ghost guns and how they can complicate investigations.