Did Texas execute an innocent man? FRONTLINE examines the conviction and 2004 execution of Cameron Todd Willingham - for the arson death of his three young children - in light of new science that raises doubts about whether the fire at the center of the case was really arson. 10/25/2011

Newly released interrogation videos show David Coleman Headley, who admitted participating in the November 2008 Mumbai terrorist attacks, desperately trying to cut a deal with FBI agents interrogating him after his arrest. "I know you have plenty of evidence against me, but really I'm just providing you more and more evidence against me, and you aren't making any arrests," he told them.

Thanks to a motion filed by FRONTLINE and ProPublica, the public has a rare opportunity to hear how confessed Mumbai terrorist David Headley tried to save himself from extradition and the death penalty after his arrest in October 2009. In this clip, Headley does his best to show the FBI agents interrogating him that his cooperation could be mutually advantageous.

A top adviser to Illinois Gov. Pat Quinn -- a close Obama ally -- on why the state withdrew from the administration's controversial Secure Communities immigration program.

"At the end of the day, when you have an immigration law that's broken, ... there will be parents separated from their children," says Cecilia Munoz, President Obama's top adviser on immigration issues.

More than one million immigrants have been deported since President Obama took office. Under his administration deportations and detentions have reached record levels. In "Lost in Detention," airing Oct 18, FRONTLINE journeys into the secretive world of immigrant detention and investigates Obama's enforcement strategies.

"As long as Congress gives us the money to deport 400,000 people a year, that's what the administration will do," says Cecilia Munoz, President Obama's top adviser on immigration issues.

In the weeks after 9/11, Capitol Hill employees were on high alert. The Friday before she opened the anthrax letter, Grant Leslie, an intern in Sen. Daschle's office, received an unusual thank-you gift for the senator from a group of Alaskan Native Americans: a bag of fur. Capitol police were called but tests showed the gift was, in fact, animal fur.

Grant Leslie tells FRONTLINE she never had much confidence in the investigation following the anthrax attacks. "I just sort of felt like nothing during this entire process was really under control," she says.

"I remember thinking: 'Oh, this is from kids. This is going to be pretty cute. I can't wait to see what they're writing to Sen. Daschle about,'" Grant Leslie tells FRONTLINE. Upon opening the letter, white powder fell into her lap.

In the days following the attacks, staffers Leslie and other staffers who tested positive for anthrax spores were put on Cipro. But Leslie, who says she's experienced no long-term side effects, was just ready to go back to work.

In the fall of 2001 envelopes carrying deadly Anthrax were delivered to U.S. Senate offices, network news divisions, and a tabloid newspaper. Five people were killed, many more infected and the nation was terrorized. Now, FRONTLINE takes a hard look at the FBI's investigation of the country's most notorious act of bioterrorism.

FRONTLINE takes a hard look at the FBI's investigation of the country's most notorious act of bioterrorism: the anthrax attacks of 2001. 10/11/2011

Adam Davidson of NPR's "Planet Money" travels to Haiti to meet a man with an unlikely tourism plan to help turn around his country's economy.

FRONTLINE investigates the illegal practice in Afghanistan of trading young boys for sexual favors. 9/27/2011

On the 10th anniversary of 9/11, FRONTLINE presents the story of Sharif El-Gamal, the charismatic property developer at the center of the Ground Zero Mosque controversy, in "The Man Behind the Mosque," airing Sept. 27.

FRONTLINE tells the dark tale of the men of Third Platoon, Charlie Company, 1st Battalion of the 506th Infantry and how the war followed them home. 9/20/2011

Former FBI agent Ali Soufan says critical CIA intelligence about Al Qaeda was not communicated to the FBI. If that information had been shared, Soufan says, "The world would be very different today."

Listening to one Al Qaeda member's grievances leads to a big get for FBI interrogator Ali Soufan -- he turns a key figure who ends up being the star witness and convicting four Al Qaeda figures at the U.S. embassy bombings trial.

The objective is always the same -- getting actionable intelligence to use in the fight against Al Qaeda -- but different subjects require different types of tactics, explains former FBI interrogator Ali Soufan.