A federal appeals court on Friday overturned Boston Marathon bomber Dzhokhar Tsarnaev’s death penalty sentence for helping carry out the 2013 attack, which killed three people and wounded more than 260 others.

The 1st U.S. Circuit Court of Appeals in Boston upheld much of Tsarnaev’s conviction but ordered a lower-court judge to hold a new trial strictly over what penalty Tsarnaev should receive for the death-penalty-eligible crimes he was convicted of.