The authorities said the 17-year-old from North Carolina had recorded the attack, which killed three people in May. “She ran with the pack — she shared in the kill,” the district attorney said.

© John Francis Peters for The New York Times

The suspect, a 43-year-old Swiss citizen, was taken into custody early on Monday, the police said.

© Denis Balibouse/Reuters

Jurors spent about seven hours discussing the high-profile case on Monday, after about 10 hours last week.

© Pool photo by Greg Derr