Transcript for Dzhokhar Tsarnaev Defense Calls 1st Witnesses
Now to the Boston marathon bombing trial. Prosecutors wrapped up its case Monday with heartbreaking testimony that left some jurors in tears. The defense now laying out its side and ABC's Tom llamas has been in the courtroom for all of it. Good morning, Tom. Reporter: Robin, good morning to you. The defense wasted no time trying to prove tamerlan, the older brother, not only directed the attack, he also provided logistics and, you're right, robin, it was likely a very long night for jurors who had to sit through hours of painful testimony with graphic images showing how dzhokhar's bomb killed a little boy. One of the biggest pieces focused on the smallest of victims, 8-year-old martin Richard. Half a dozen jurors wiping away tear, the testimony and photos showing not a single piece of the boy's body spared from shrapnel, burns or injury. Agonizing evidence as the government rested its case in the Boston marathon bombing trial on Monday. Prosecutors also showing this haunting photo, that's the Richard family watching the marathon two years ago. Martin by the fence, mom to the left with the brown hat and the big smile. But look closely. Lurking in the background behind the tree in that white hat, dzhokhar tsarnaev. The prosecution has brought the jury to the scene of that awful incident. All of which is pretty powerful stuff to show that he was, indeed, a terrorist. Reporter: But the defense now has its chance to try calling their first witnesses Monday. They're looking to prove dzhokhar was a puppet controlled by his older brother tamerlan. The jury seeing that cell phone and gps record suggests he wasn't there when tamerlan bought and later built the pressure cooker bombs. And this video, showing tamerlan leading the way down Boylston street, the defense hoping the jury takes pity on the little brother they say tagged along. I think he's guilty. Reporter: The bomb dzhokhar planted took heather Abbott's leg. It's unclear if dzhokhar will testify but from what heather has seen in court it's not sorrow he's been expressing. I was somewhat surprised at his demeanor in court. I would have thought that he would have some sort of reaction. I really can't understand how a person like that thinks. Reporter: And so far the defense has called no character witnesses, only an FBI photographer and a forensic investigator. Yesterday I asked one of dzhokhar's lawyers if he will take the stand. She had no comment. Robin. We'll wait and see. Tom, thank you.
This transcript has been automatically generated and may not be 100% accurate.