Claudio Rojas was released from an immigration detention center in Broward County in August. Shortly after, the Argentine citizen obtained his work permit, a driver’s license and the opportunity to resume his daily life.

Yet when Rojas recently showed up for his weekly check-in at the Immigration and Customs Enforcement office in Miramar, agents placed an electronic monitor on his right ankle.

Now he doesn’t know if or when it will be removed.

“After months of being out without representing any danger, now they put me on this device,” said Rojas, who in 2012 was held at the private Broward Transitional Center in Deerfield Beach for seven months despite not having a criminal record. “I don’t understand what the point is.”

The federal government says it is less expensive to monitor undocumented immigrants through phone calls, at-home check-ins or electronic monitors than to keep them in jail. Recently, to save money, the government released more than 2,000 undocumented immigrants nationally.

However, although the jail population fluctuates daily, the 700 beds at Broward Transitional remain mostly full. And it’s not clear how many immigrants, like Rojas, have been released from the center and are now in the Intensive Supervision Appearance Program.

Nestor Yglesias, an ICE spokesman, said he didn’t have the local number of immigrants in the monitoring program. But he said that at the national level the daily average is 21,634.

Several immigrants with electronic ankle monitors and immigrant rights activists questioned whether the real motivation of monitoring undocumented men and women is to generate more revenue for BI Inc., the private company with the only contract to provide the service.

In 2010, a year after BI Inc. obtained the contract with ICE, the company was bought by GEO Group Inc., a controversial private prisons corporation based in Boca Raton. GEO Group also owns Broward Transitional Center, the only private detention center for immigrants in Florida.

“This is definitely about money; it’s a business,” said Mohammad Abdollahi, a South Florida-based activist from the National Immigrant Youth Alliance. “If a person qualifies for an ankle bracelet in the first place, why would ICE jail him for months or even years, which costs a lot more money to the federal government?”

Yglesias said that the alternative methods to detention are used on individuals who represent low risk to public safety and that the supervision of each person is based on an analysis of risk-of-flight or failure to comply with the other conditions of their release.

However, even the secretary of the Department of Homeland Security, which supervises ICE, said that she doesn’t understand why immigrants who qualify for alternative methods to detention have remained jailed for several months.

“We are investigating the situation,” Janet Napolitano said in an interview with CBS News in February.

The federal government pays BI Inc. between 17 cents and $17.69 daily for every undocumented immigrant in the monitoring program, depending on the level of vigilance in each case.

The cost per day for each immigrant in detention varies from jail to jail. At BTC the price is $120 per day for each bed. Several civil rights organizations have estimated a national average of $122 to $164 per day for each detainee. This would represent from $44,530 to $59,860 per person for a year of detention.