Question: When was the indie rock band which has a member of Broken Bells as the lead vocalist and guitarist formed? 
Sentence (from "Broken Bells"): The previous live band included Conor Oberst and the Mystic Valley Band sidemen Nate Walcott and Nik Freitas, and Jonathan Hischke and Dan Elkan, both ex-members of Hella.
Relevant evidence: No