Federal authorities are working to determine the immigration status of people who entered the US with the help of First World Immigration Services.
According to Chicago Tribune, "As part of a widening probe into an international terror plot rooted in the city, US authorities are sharpening their sights on First World Immigration in search of possible acts of immigration fraud."
Prosecutors charge that the immigration centre served as a front in the Chicago-based terror plot.
They also allege that Rana knew in advance of the 2008 Mumbai terror attacks that killed 166 people.
According to court filings, Rana allegedly conspired to bring foreigners to the US under false pretences.
In e-mail conversations, Rana advised an alleged member of Lashkar-e-Toiba about loopholes to get individuals into the US.
"Whenever you find easy way to come to US, immediately think there is a catch to it," Rana allegedly wrote in an e-mail.