Story highlights Justice Department tells Alabama it has the authority to investigation immigration-based discrimination

Alabama's attorney general questions the right of the federal government to launch the investigation

The Justice Department is suing Alabama, South Carolina, and Arizona over tough immigration laws

Alabama's law includes a mandate for public schools to investigate students' immigration status

The Justice Department sent a letter to the Alabama's attorney general Friday asserting that federal civil rights lawyers have the authority to investigate Alabama schools for discrimination based on immigration status -- and will continue to do so.

State Attorney General Luther Strange had questioned the department's authority to demand extensive records on school enrollment and attendance in the current school year following passage of a state law designed to curb illegal immigration.

The law -- enacted last spring -- includes a mandate for public schools to inquire about the immigration status of students, among other things. A U.S. appeals court granted a Justice Department request for an emergency injunction for that portion of the law, but allowed other controversial sections to be enforced.

Friday's letter from Assistant Attorney General for Civil Rights Thomas Perez responded directly to a letter Strange sent Wednesday demanding to know the Justice Department's legal basis for its requests of 39 school districts. In response, Perez noted his department had received multiple complaints from Alabama and cited three federal statutes, including the 1964 Civil Rights Act.

Perez, the administration's top civil rights official, pointedly asked Strange why he was involving himself in the issue at all.

"It is our understanding that you do not represent the school districts that we have contacted. Please let us know if that understanding is correct so that we may proceed accordingly," Perez said. "As we receive additional information, the Civil Rights Division and other Federal agencies will be evaluating the potential for violation of federal laws in Alabama, including civil rights laws."

Alabama has been told to provide the Justice Department's requested data by November 14.

Alabama officials, however, received a strong show of support Friday on Capitol Hill, where three leading southern senators announced their intention to introduce legislation barring the Obama administration from participating in lawsuits over new immigration laws in Arizona, Alabama, and South Carolina.

The Justice Department has sued all three states, and is considering similar action against Utah, Indiana, and Georgia.

Sens. Jim DeMint, R-South Carolina, Jeff Sessions, R-Alabama, and David Vitter, R-Louisiana, said they would attempt to block funding for the lawsuits.

"We're working to stop these politically driven lawsuits by cutting off the ability for the Obama administration to use taxpayers' money to pay for them," Vitter said.

DeMint called it "absurd" for an administration "which has failed to enforce the nation's immigration laws" to try to stop South Carolina, Alabama, and Arizona "from taking commonsense steps to protect citizens and uphold the law."