Last year, the Obama administration set new records for detaining and deporting immigrants who were inside the U.S. illegally. Homeland Security Secretary Janet Napolitano recently indicated that the 2011 numbers will be even higher, resulting in the removal of about 400,000 people.

The high deportation numbers — and Secure Communities, the controversial program behind them — have caused an outcry from advocacy groups, politicians and even some law enforcement agencies across the country.

Cecilia Muñoz, Obama’s top adviser on immigration issues, spoke with FRONTLINE correspondent Maria Hinojosa for our upcoming film Lost in Detention, and explained why the administration plans to keep detaining and deporting record numbers of illegal immigrants:

Secure Communities is a high-tech information-sharing program between Immigration and Customs Enforcement (ICE) and local law enforcement. But critics, including three Democratic state governors, say the program is detaining and deporting low-level offenders or people without criminal records, contrary to the administration’s stated goal [PDF] of deporting only “aliens who are convicted of a serious criminal offense.” Muñoz addresses the criticism:

The adjustments Muñoz refers to include a Department of Homeland Security [DHS] prosecutorial discretion memo [PDF] aimed at giving ICE guidance about who to detain and deport, and a promise to review 300,000 pending deportation cases to identify people who have lived in the U.S. for years without committing crimes.

Stay tuned for our full film on Oct. 18 (check local listings), which will feature one family directly impacted by Secure Communities, as well as reporting on Obama’s immigration conundrum and how it might impact the 2012 election.