Criminal immigration enforcement by the federal government is steadily growing under the Obama administration and has reached the highest levels seen during the presidency of George Bush, despite fewer people living illegally in the United States.

The latest numbers contrast with now-frequent statements being made by elected officials in Texas, Arizona and elsewhere who say the Obama White House does not want to enforce security on the nation’s border with Mexico.

There were nearly 15,000 criminal immigration cases referred for prosecution by Customs and Border Protection during March and April of this year, the most since a similar period in 2008 when more than 16,000 cases were referred. The Department of Homeland Security’s other major investigative agency, Immigration and Customs Enforcement, reported a larger number of new criminal prosecutions during the same two-month window than any other since its establishment in 2005. The total was 4,145.

The new look at this year’s cases comes from researchers at Syracuse University’s Transactional Records Access Clearinghouse, which specializes in federal law enforcement statistics. TRAC obtained the data from the Justice Department through a Freedom of Information Act request.

Federal immigration enforcement began to rise starting around early 2008 during the Bush administration after authorities made progress in implementing the Secure Border Initiative, first unveiled by former homeland security chief Michael Chertoff in late 2005 when protests over illegal immigration grew to a fever pitch.

The program called for deploying thousands of new border patrol agents and investigators, lining the southwest boundary with hundreds of millions of dollars in electronic surveillance equipment, beefing up work site enforcement and detaining suspected immigration violators rather than letting them go until a scheduled deportation hearing could occur.

TRAC’s figures show that while prosecution referrals made by CBP began to dip over time on Obama’s watch, they turned around at the beginning of this year and started an upward trend. The chart above depicts this pattern since November. The month-to-month reporting of ICE cases, meanwhile, is erratic by comparison but nonetheless shows a similar hike that started around January and ultimately led to the two-month, record-breaking high.

In a story about TRAC’s new analysis, the Associated Press pointed to statistics from the Department of Homeland Security showing that as of January 2009, about one million fewer illegal immigrants (10.8 million total estimated) were residing in the country compared to a 2007 peak. Deportations have nonetheless climbed to new levels and stayed there during the Obama administration, more than doubling from 186,000 in 2007 to 388,000 last year.

Immigration enforcement cases also continue to clog the federal docket, jumping even in U.S. court districts not located near the southwest border with Mexico, according to TRAC. New cases in non-border districts climbed over 50 percent between February and April of this year to 1,148, while the rate nationwide during that time went up 42 percent.

G.W. Schulz is a reporter for Reveal, covering security, privacy, technology and criminal justice. Since joining The Center for Investigative Reporting in 2008, he's reported stories for NPR, KQED, Wired.com, The Dallas Morning News, the Chicago Tribune, the San Francisco Chronicle, Mother Jones and more. Prior to that, he wrote for the San Francisco Bay Guardian and was an early contributor to The Chauncey Bailey Project, which won a Tom Renner Award from Investigative Reporters and Editors in 2008. Schulz also has won awards from the California Newspaper Publishers Association and the Society of Professional Journalists’ Northern California Chapter. He graduated from the University of Kansas and is based in Austin, Texas.