When people say that “crime pays” it’s assumed they’re talking about criminals. But a recent report by the Associated Press reveals that crime — at least the housing of people in detention centers — means big profits for private prison companies.

The AP report says that the federal government will pay about $2 billion this year to private, for-profit companies to house people, mostly undocumented workers, in detention centers.

The immigration debate reveals legitimate concerns on both sides. But private companies making big profits from immigration enforcement is not something most people would support.

The issue is even more troubling when the political activities of the industry are known.

The three dominant private prison companies — Corrections Corporation of America (CCA), the GEO Group and Management and Training Corp. — have spent $45 million on campaign contributions and lobbying. As expected, the industry denies its campaign donations are intended to influence immigration policy.

But they are making more money with the recent crackdowns on illegal immigration. And not only do the companies make money housing people held in detention centers, they also profit from providing health care and transportation services to detainees.

Despite a drop in illegal immigrants coming into the United States, due to the weak U.S. economy and stepped-up immigration enforcement, the private companies have seen their profits jump.

Beyond the $2 billion U.S. taxpayers will spend housing detainees in some 250 sites this year, plans call for new facilities to be built over the next few years to house an additional 400,000 people. The cost to taxpayers will go up accordingly.

In the 1990s, Congress called for more detention of undocumented workers. After the private prison companies increased their lobbying efforts, the budget for U.S. Immigration and Customs Enforcement (ICE) grew to $4.7 billion from $3.5 billion.

Beyond housing undocumented people, private prisons also hold immigrants convicted of crimes. Ten years ago, the Federal Bureau of Prisons paid $760 million to house 3,300 convicted criminal immigrants in prisons run by CCA. Today, the cost is $5.1 billion for housing 23,000 people in private facilities.

The growth in private detention centers has exploded to the point where nearly half the detention centers are privately run, up from 10 percent a decade ago.

Advocates for private prisons say that they operate at a lower cost than government-run facilities. Beyond examining that claim, federal officials should be looking for less-expensive alternatives to detention centers.

In addtion, taxpayers should demand scrutiny of “get tough on illegal immigration” advocates, given the connection between tougher laws and the for-profit prisons’ lobbying activities.

Profiting from immigration detention centers is not unlike the “three strikes” laws that were enacted a few decades ago that seemed to express public sentiment to get tough on crime. Behind the scenes, however, unions for prison guards were pushing the “three strikes” laws because it meant more people being locked up, more prisons and more dues-paying prison guards.

Today, strained by skyrocketing prison costs, most states are questioning the rapid growth of prisons and their costs. For-profit detention centers should not escape review.

Citizens are rightly concerned about crime, including illegal immigration. But taxpayers should be equally concerned about prison costs and finding the most effective ways to deal with crime, especially non-violent crime, including immigration violations.

Suspicions are rightly raised when for-profit prison companies spend tens of millions of dollars in political campaigns and lobbying to encourage policies that fatten their bottom lines.

Congress should take a hard look at private, for-profit prison companies to ensure that crime does not pay — at least that taxpayers are not being fleeced by companies exerting political influence and pushing tough-on-crime rhetoric and new laws.