Left: JOHANNES HIRN/LANDOV; Right: Handout

Marathon bombing suspects Tamerlan Tsarnaev (left), pictured in 2009, and Dzhokhar Tsarnaev, in a yearbook photo.

Left: JOHANNES HIRN/LANDOV; Right: The Lowell Sun/Julia Malakie/AP

Tamerlan Tsarnaev practiced boxing at the Wai Kru Mixed Martial Arts center in Boston in 2009 (left), and received a boxing trophy in 2010.

Left: BOSTON REGIONAL INTELLIGENCE CENTER; Right: Robin Young vis AP

Dzhokhar A. Tsarnaev, pictured at a Cambridge gas station early Friday morning (left) and after graduating from Cambridge Rindge and Latin High School.

ANNE REARICK

Tamerlan Tsarnaev got his hands laced at a Golden Glove event in Lowell on 2006 (left) and posing with former professional boxer Micky Ward.

Glenn DePriest/Getty Images)

Tamerlan Tsamaev (left) during a boxing in Utah in 2009.

VKontakte/AFP/Getty Images

An undated image of what appears to be Dzhokhar Tsarnaev taken from VKontakte, a Russian social media site.

Bob Leonard

Dzhokhar A. Tsarnaev (left) and Tamerlan Tsarnaev were pictured on Boyston Streen shortly before the Boston Marathon bombings.

David Green/AP

What appears to be Dzhokhar A. Tsarnaev (left, in white hat) is shown walking away after the Marathon bombings on Monday.

CBS NEWS/AFP/Getty Images

This image shows Tsarnaev, who was captured after being found hiding in a boat in a Watertown backyard.

Reuters

Medical workers treated Dzhokhar A. Tsarnaev moments after he was captured.