Detentions of undocumented immigrants have become big business for private companies operating prisons in states like Arizona, which is why they promote anti-immigrant laws like SB1070, a group of activists said.

"Contractors come to Arizona attracted by the increase in militarization and the criminalization of immigrants - it's very easy to use undocumented immigrants for that purpose," Isabel Garcia, director of the Tucson-based Derechos Humanos/Human Rights Coalition, told Efe on Friday.

Garcia said that a perfect example of this "lucrative business" can be observed at the Tucson federal court where from Monday to Friday an average of 80 undocumented immigrants are tried.

"For imprisoning the undocumented we're paying between $13 million and $15 million a month to private companies," Garcia, an attorney who heads the public defender's office in Pima County, said.

Her criticisms are confirmed by a study released this week by the Detention Watch Network, which analyzes the impact and influence of the for-profit prison industry on the system of immigration detentions in the United States.

Three of the five private corporations that hold contracts with U.S. Immigration and Customs Enforcement, and for which data on political lobbying is available, invested $20.43 million in such efforts between 1999 and 2009, DWN found.

The largest for-profit prison company in the United States, Corrections Corporation of America, spent by far the most (a little more than $18 million), while GEO Group Inc. spent $2.06 million.

In Arizona, CCA operates six prisons, of which three are detention centers for the undocumented, while the GEO Group Inc. operates another two jails and a detention center.

"The undocumented have become the principal source of business of these companies, it's the most promising segment of the population for them," Garcia said.

She said that Arizona is "the center of operations" for corporations receiving "millions and millions" of dollars from the federal government and the states for locking up undocumented immigrants.

"Deporting immigrants isn't enough anymore - first they criminalize them so they can justify jailing them through these private companies," the attorney said.

In her opinion, the problem began at the same time that state prisons began to be privatized.

Karla Hernandez, representative of the neighborhood organization Corazon de Tucson (Heart of Tucson), told Efe that these companies are investing thousands of dollars in lobbying to push anti-immigrant laws at the state level such as Arizona's SB1070, which aims to criminalize undocumented immigrants.

"In Arizona we see families being separated," she said.

Hernandez added that immigrants are not seen as human beings but rather as "dollar signs" for corporations like CCA and GEO Group Inc.