article_snippet.sent: defense took just two days to call four witnesses, federal court has .
article_snippet.sent: scheduled about two weeks' worth of testimony as Tsarnaev's .
article_snippet.sent: lawyers make the case to spare his life.
article_snippet.sent: Few details are known about who the defense lawyers will call to .
article_snippet.sent: testify as all witness lists in the trial have been filed under .
article_snippet.sent: to Boston or if members of his family will testify or simply observe the . proceedings.
article_snippet.sent: Another unanswered question is whether Tsarnaev will speak .