Yemen has taken center stage in the war against Al Qaeda, with President Barack Obama recently describing the country as a hub for foreign terrorists.

Amid the instability following the ouster of Yemeni president Ali Abdullah Saleh last year, Al Qaeda in the Arabian Peninsula (AQAP) has been called the "most active and lethal Qaeda affiliate."

In a FRONTLINE special report, Guardian journalist Ghaith Abdul-Ahad delves deep into his investigation of the insurgent group as few have before; according to PBS's release on "Al Qaeda In Yemen," Abdul-Ahad "travels deep into Yemen's radical heartland to look at how members of Al Qaeda, describing themselves as the group Ansar al-Sharia, have seized control of cities and towns and are winning support among some in the local population—and recruiting militants—by administering scarce resources."

The report originally aired Tuesday, May 29, 2012, at 10 p.m. EST. Watch the full report in the video above.