Carrie Johnson

It's one of the smallest law enforcement agencies in the federal government, but the Bureau of Alcohol, Tobacco, Firearms and Explosives has sure had a busy couple of weeks.

Dozens of its agents raced to Boston, where they analyzed bombs left near the finish line of the marathon. Others went south to Texas, where a fertilizer plant exploded under mysterious circumstances. Members of the ATF's national response team are still on the scene in tiny West, Texas, sifting through rubble at the blast site, near a crater that's 93 feet wide.

Footage from surveillance cameras along the Boston Marathon route gave the FBI early clues about the bombing suspects. And prosecutors say they'll use some of those images to try to prove their criminal case against 19-year-old Dzhokhar Tsarnaev. But the proliferation of cameras in America's big cities is raising some tricky questions about the balance between security and privacy.

It was pictures of two brothers taken by a camera outside the Lord & Taylor department store that provided the first glimpse of the men who allegedly bombed the Boston Marathon.

President Obama's nominee to lead the Labor Department has been one of the most aggressive advocates for civil rights in decades. Tom Perez prosecuted a record number of hate crimes cases and extracted huge settlements from banks that overcharged minorities for home loans.

But some Republican lawmakers say those same qualities give them pause about voting to confirm Perez as a Cabinet member.

'Making A Huge Difference'

Steven Nolder joined the federal public defender's office when it opened in Columbus, Ohio, nearly 18 years ago. Nolder handled his share of noteworthy cases, including the first federal death penalty trial in the district and the indictment of a former NFL quarterback embroiled in a ticket fraud scheme.

Lately, Nolder says, his professional world has turned upside down.

Robert Mueller became FBI director just days before the attacks of Sept. 11, 2001. Since then, he's been the U.S. government's indispensable man when it comes to national security.

But Mueller's term has expired, and the clock is ticking on an unprecedented extension that Congress gave him two years ago.

The first time the Obama White House thought about a replacement for Mueller, back in 2011, officials threw up their hands and wound up begging him to stay. Congress passed a special law to allow it. Then Republican Sen. Charles Grassley of Iowa put his foot down.