"He woke up under so much drugs, asked for a paper and pen and wrote, 'bag, saw the guy, looked right at me,' '' Chris Bauman said Thursday in an interview.
Those words may have helped crack the mystery of who perpetrated one of the highest-profile acts of terror in the United States since the 2001 assault on New York City and the Washington area, one that killed three people and wounded scores.
The Boston area was on lockdown Friday morning after law enforcement officials killed one suspect in the bombing and were hunting another, following a night of violent clashes between the two men and authorities that killed a Massachusetts Institute of Technology campus policy officer.
The suspect, Dzhokar Tsarnaev, 19, was captured Friday night after a large-scale manhunt.
The individual identified as the second suspect was his brother, Tamerlan Tsarnaev, 26, according to the official. He was killed early Friday by law enforcement.
Jeff Bauman's face-to-face confrontation with one of them may have yielded key clues in the manhunt, which intensified Thursday after the Federal Bureau of Investigation released video images of two men.
While still in intensive care, Bauman gave the FBI a description of the man he saw, his brother said.
Bauman's information helped investigators narrow down whom to look for in hours of video of the attack, he said.
In the images released Thursday, both men wear hooded sweatshirts under dark jackets; one wears a light-colored baseball cap turned backward on his head, while the other wears a dark baseball cap facing forward.
Both are carrying large backpacks.
"I've had many times alone with him, and yes, he told me every single detail," Chris Bauman said.
Paul Bresson, an FBI spokesman in Washington, declined to comment on specific tips in the investigation. Two FBI agents interviewed at the Boston office declined to confirm or deny the account.