When Dzhokhar Tsarnaev got a text from a friend asking him if he was one of the two men shown in FBI-released photos of Boston bombing suspects, his reply was short and light: LOL.
Other messages from the teenager followed, including "You better not text me" and "Come to my room and take whatever you want," according to an FBI affidavit released Wednesday. His friend took the texts as jokes, as if Tsarnaev found humor in the mere idea that he could be responsible for such horror.
But when Dias Kadyrbayev showed one of their mutual friends that last text, the friend wasn't laughing.
"He believed he would never see Tsarnaev alive again," the affidavit said of Azamat Tazhayakov.
What Kadyrbayev, Tazhayakov and another friend, Robel Phillipos, did next is the subject of a detailed, sometimes complex FBI affidavit released on Wednesday. That document lays out the federal case as to why the three young men, like their friend Tsarnaev, are now in federal custody.
The charges levied Wednesday do not accuse the three friends of having any involvement in the April 15 attack. Lawyers for two of the men insist that their clients are cooperating and deny any such role.
Did they suspect Tsarnaev could be responsible for such bloodshed? According to Tazhayakov's account in the affidavit, while they were eating together about a month before the bombing, Tsarnaev told them he knew how to make a bomb. Less clear, and more critical to their case, was when they concluded Tsarnaev was possibly involved in the Boston attacks, and what they did afterward.
And were their actions -- both in tossing a backpack belonging to Tsarnaev and how they dealt with federal investigators -- criminal? That may be decided by a jury, unless the charges are dropped or plea agreements are reached.
What is known is that the four young men -- Tsarnaev, Phillipos, Kadyrbayev and Tazhayakov -- enrolled in fall 2011 at the University of Massachusetts-Dartmouth and became friends.
Kadyrbayev and Tazhayakov were in the United States on student visas from Kazakhstan, and spoke Russian as did Tsarnaev. Phillipos, a high school classmate of Tsarnaev, called Cambridge, Massachusetts, his home, as did Tsarnaev.
They hung out together, went out together -- including to New York's Times Square, as a 2012 photo with Kadyrbayev, Tazhayakov and Tsarnaev showed. Kadyrbayev told investigators that he'd gotten to know Tsarnaev's family and had repeatedly gone to his home when the family lived in Cambridge.
And they spent time together after the deadly Boston Marathon blasts.
Two days after that attack, on April 17, Kadyrbayev told law enforcement officers that he drove to Tsarnaev's dormitory room on the campus of their southern Massachusetts school and texted to his friend to come down to meet him. Tsarnaev -- who had noticeably shorter hair at the time, Kadyrbayev recalled -- came down, the two chatted, and that was that.
Tsarnaev spent that night, until around midnight, at the New Bedford apartment of Tazhayakov. The next afternoon, Tazhayakov went to class on campus and got a ride home from Tsarnaev, the federal affidavit states.
That happened not long before 5 p.m., when the FBI released its first photos of the two Boston bombing suspects. One wore a dark baseball cap, a light collarless shirt and a dark-colored jacket. The other had a hooded sweatshirt, black jacket and a white baseball cap turned backward.
It was the latter suspect that caught Phillipos' eye. And it also got the attention of Kadyrbayev, when he got home that night and turned on the TV.
Could that be Dzhokhar?
The night of Thursday, April 18, authorities say that Dzhokhar and Tamerlan Tsarnaev were on the run -- allegedly responsible for killing a Massachusetts Institute of Technology police officer, carjacking a Mercedes SUV, then tossing explosives and trading gunfire with authorities on a high-speed chase through Boston suburbs.
Dzhokhar Tsarnaev's friends were active that night as well, some 60 miles south.
While the three 19-year-olds offered slightly different details and time frames, a common chain of events emerges from their remarks to investigators as laid out in the FBI affidavit.