Dzhokhar Tsarnaev Pleads Not Guilty to 30 Counts
07/10/2013 AT 04:00 PM EDT
In his first public appearance since being arrested April 19, he entered the plea Wednesday at his arraignment in federal court in Boston.
For first one, he leaned toward a microphone and said, "Not guilty," in a Russian accent. He then said not guilty repeatedly about a half-dozen more times.
Federal prosecutors are weighing whether to pursue the death penalty for the 19-year-old Tsarnaev.
Authorities say he and an older brother, Tamerlan, planted two bombs, which killed three people and wounded more than 260 at the April 15 marathon. The older brother was killed three days later following a shootout with police. Dzhokhar Tsarnaev was later found hiding in a boat in a suburban backyard.