‘‘Just knowing him, it’s hard for me to face the fact that he did it,’’ said Alvarez, 19, of Cambridge.
Prosecutors say Tsarnaev, a Muslim, wrote about his motivations for the bombing on the inside walls and beams of the boat. He scrawled that the U.S. government was ‘‘killing our innocent civilians,’’ and also wrote: ‘‘We Muslims are one body, you hurt one you hurt us all.’’
Martin Richard, 8, Krystle Marie Campbell, 29, and Lingzi Lu, 23, were killed by the two bombs, which were fashioned out of pressure cookers, gunpowder, nails and other shrapnel. Numerous victims lost legs.
Associated Press writer Arsen Mollayev in Makhachkala, Russia, contributed to this report.