I first saw Tsarnaev at his arraignment July 2013. He was taller than I'd expected and still healing from gunshot wounds incurred during the Watertown shootout and his subsequent capture. Back then, he seemed defiant, speaking in a Russian accent, which his wrestling buddies told me he had never done before.
But since his trial began in January, his defiance has given way to resignation. For the most part, Tsarnaev has seemed disengaged, showing little emotion, fidgeting in his seat as if he is bored or perhaps impatient.
He knows there are two possible outcomes.
He will be sentenced either to death or to life in solitary confinement in a Supermax prison. Tsarnaev is ready to accept his punishment, or at least that's what his lawyers say.
Last month, 21-year-old Tsarnaev was found guilty of using a weapon of mass destruction, guilty of conspiracy, and guilty of actions that caused the death of four people and irreparably changed the lives of 260 others injured by the bombs he and his brother detonated at the Boston Marathon in 2013.
In court, people have wept as they've listened to survivors testify about how it was such a great day until "that moment" when the blast lifted spectators into the air and dropped them bleeding onto the sidewalk.
It is the story of the brothers' last hours together that had jurors on the edge of their seats as they watched surveillance videos showing Dzhokar, then 19, and Tamerlan, 26, trying to make their escape after their photos were made public.
Their flight began with another murder. Surveillance video shows two shadowy figures crossing MIT campus, surprising an officer as he sat in his police cruiser. The brake lights flash brightly as Officer Sean Collier apparently struggles with the men who are trying to steal his gun. The struggle lasts 50 seconds and then another flash -- the fatal shot fired at point blank range.
The jury heard how the brothers carjacked an SUV driven by Chinese national Dun Meng, and they heard how Tamerlan told Meng he was behind the attack.
"He asked, 'You know who did it? I did it and I just killed a policeman in Cambridge,' " Meng testified.
Meng described how they pulled over at a gas station, how he counted the steps in his mind, slipping off his seatbelt and opening the car door in a single gesture, then bolting across the street to another gas station. Security cameras capture the fear on Meng's face as he begs the store clerk to call 911 and then crawls into a storage room to hide.
Other surveillance video shows the younger Tsarnaev inside the gas station store carefully picking out chips, drinks, snacks -- possibly for a drive to New York where prosecutors say the Tsarnaev brothers intended to explode the remaining pressure cooker and homemade pipe bombs. After Meng's escape, Tamerlan looks unhappy as he races to the door to get his brother who puts down the armful of snacks and races out the door. In the hours that follow, one brother died. The other became the subject of a massive manhunt that ends in his capture.
Prosecutors had little difficulty convincing the jury of Tsarnaev's guilt. Yet, in the penalty phase, it is Tsarnaev's lawyers who have tried to focus the jury less on what he did and more on who he was.
They have done this by showing the jury two starkly different images of the brothers. Tamerlan was portrayed as manipulative, controlling, a dangerously aggressive, frustrated boxer who was unemployed and who traveled to Dagestan to wage jihad. Dzhokhar, on the other hand, was portrayed as a gifted student and athlete, eager to learn and please his teachers. A young man who ultimately could not separate himself from the destructive path of his family.
Several of his teachers from grade school have testified on his behalf, smiling as they fondly remembered the child they believed had so much promise for the future. High school and college friends who once adored Tsarnaev and his goofy humor and kindness now feel betrayed.
Only toward the end did Tsarnaev seem to show any emotion.
Smiling back at his teachers and dabbing a tear after aunts and cousins testified about the child they knew whose kindness brought out the best in people. People who once saw so much potential, who now see a life wasted.