WASHINGTON - Immigration officials now have access to the fingerprints of every person booked into jail in all 25 U.S. counties along the Mexican border, Homeland Security Secretary Janet Napolitano announced Tuesday, touting the program as a way of identifying and deporting "criminal aliens."

Napolitano's announcement came as immigrant-rights activists criticized the fingerprinting program, known as Secure Communities, after obtaining documents showing that more than one-quarter of those deported under its auspices had no criminal records.

The program "essentially co-opts police into doing the job of the federal government," said Sunita Patel of the Center for Constitutional Rights, one of several groups that forced the disclosure of documents through a Freedom of Information Act lawsuit.

That charge is baseless, DHS officials said. Secure Communities gives Immigration and Customs Enforcement (ICE) the ability to check the fingerprints of those arrested against a database that will show whether they have ever been deported or otherwise had contact with immigration agents.

If ICE determines that the person is in the country illegally, federal agents can institute deportation proceedings. Records show that happens in some cases, but not all.

"The Secure Communities initiative reflects ICE's ongoing commitment to smart, tough enforcement strategies that help ensure the apprehension of dangerous criminal aliens," ICE Director John Morton said. "Expediting removals decreases the amount of time these individuals spend in ICE custody - saving taxpayers money and strengthening public safety."

By some estimates, as many as 1 million illegal immigrants now living in the U.S. have committed crimes, Morton has said. ICE often is unaware of them, even when they are in jail or prison.

Secure Communities makes such notifications automatic. ICE says the program identified more than 262,900 illegal immigrants in jails and prisons who have been charged with or convicted of criminal offenses, including more than 39,000 charged with or convicted of violent offenses or major drug crimes.

DHS has expanded the initiative from 14 to 544 jurisdictions in the past 18 months. ICE plans to implement the program nationwide by 2013.

Some of the immigrants deemed to be criminals have been convicted of minor crimes, such as disorderly conduct.

The documents obtained by the immigration-rights groups show that a total of 47,000 people have been removed since 2008 after being flagged under the Secure Communities fingerprint-matching program. Of those, about 28 percent were non-criminals, meaning they were arrested and booked, but not convicted.