Details of suspects emerge as manhunt continues

BARCROFT MEDIA PHOTO

In two photos from 2009, Tamerlan Tsarnaev is shown inside the Wai Kru Mixed Martial Arts center in Boston (left) and arriving at the center (right). The suspected Marathon bomber died after a shoot-out with police Thursday night, while his brother remains at large.

ANNE REARICK

In two photos from 2006, Tamerlan Tsarnaev got his hands laced at a Golden Glove event in Lowell (left) and posed with former professional boxer Micky Ward.

FBI, BRIC/AP

Authorities are searching for Dzhokhar Tsarnaev, the suspect seen in FBI photos in a white cap.

jim davis/globe staff

Congress Street in the Financial District was deserted on Friday afternoon.

jim dais/globe staff

An American flag fluttered at the scene of the murder of MIT police officer Sean Collier.

jonathan wiggs/globe staff

A nearby family brought items to Collier's home in Somerville.

jim davis/globe staff

Beacon Street in Boston was empty Friday afternoon.

david l. ryan/globe staff

Police took up positions in Watertown during the manhunt.

David l. ryan/globe staff

Police searched a building in Watertown Friday in the hunt for a suspected Boston Marathon bomber.

Aram Boghosian for The Boston Globe

Residents watched police in front of a building in Watertown.

Essdras M. Suarez/Globe Staff

Governor Patrick and Mayor Menino conducted a press conference at Watertown Mall Friday afternoon with other officials.

josh reynolds for the boston globe

Officers took a man into custody at Norfolk Street in Cambridge Friday morning.

Josh Reynolds for the Boston Globe

A pair of women who were neighbors of the suspects on Norfolk Street in Cambridge reacted as they spoke to officers.

Aram Boghosian for The Boston Globe

SWAT teams moved into position in Watertown Friday morning during a massive manhunt for one of the Marathon bombing suspects.

Matt Rourke/AP

Police evacuated a neighborhood in Watertown Friday as they hunted for one of the Marathon bombing suspects.

Jonathan Wiggs/Globe Staff

A MIT police officer stood by his cruiser Friday. Late Thursday, a MIT officer Sean Collier was shot and killed.

Aram Boghosian for the boston globe

Teams moved into position in Watertown while searching for the Marathon bombing suspect who was still at large.

Hunt for bombing suspect

As he fled in car, suspect ran over wounded brother

Dzhokhar A. Tsarnaev ran over his own brother as he fled police, officials said. Police continue to search Watertown for the Marathon bombing suspect.