A 27-year-old man whose legs were blown off by the Boston bombings reportedly helped FBI agents identify one of the suspects, saying the man looked him in the eye as he placed a bag filled with explosives at his feet. 

Jeff Bauman was waiting for his girlfriend to cross the finish line just before 3 p.m. Monday when a man wearing a cap, sunglasses and a black jacket dropped a bag at Bauman's feet, his brother, Chris Bauman, told Bloomberg News.

Two and a half minutes later, the bag exploded, shredding Bauman's legs. A photo of his bloodied body being rushed by wheelchair from the scene has become an iconic image of the terrorist attack. 

"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 told Bloomberg News.

Bauman's description to investigators at his bedside reportedly helped them zero in on suspect Tamerlan Tsarnaev, who was killed early Friday in a shootout with police.  

Bauman was rushed to Boston Medical Center, where both his legs were amputated from the knee down. His family learned of his fate only after seeing the grisly image of their son in news reports.

One volunteer, dubbed the the "Cowboy Hat Hero," is being credited with helping to save Bauman's life. The man, identified as Carlos Arredondo, used some pieces of cloth to tie tourniquets around Bauman's mangled legs before getting him onto a wheelchair.

Arredondo's son, Alex, died in Iraq in 2004. He was reportedly at the marathon to support "Tough Ruckers" – a group that runs in full military gear to honor fallen comrades.