U.S. Justice Department agents are looking into allegations that the state of California and its courts are denying voting rights to residents with intellectual disabilities, according to media reports Wednesday. 

The Justice Department disclosed a letter sent last week to California’s Supreme Court Chief Justice Tani Cantil-Sakauye and Secretary of State Alex Padilla, asking for detailed records on how and why certain residents with disabilities were disqualified from voting, according to the Los Angeles Times. The department is now investigating whether the state's voting practices violated the Americans with Disabilities Act.

The probe was opened after a 2014 complaint by the Disability and Abuse Project, an advocacy group, which alleged widespread abuse of California’s limited conservatorship program, wherein developmentally disabled citizens have an appointed caretaker who has special rights over them.

“We have discovered many policies and practices of agencies and individuals who operate the Limited Conservatorship System that routinely violate the constitutional and statutory rights of ... limited conservatees,” Assistant U.S. Attorney Vincente Tennerelli said in the complaint.

The group accused the Los Angeles Superior Court of declaring people with intellectual disabilities unfit to complete voter registration forms without conducting a proper investigation into their competencies. It said that once someone is found incapable of registering, their names were permanently removed from voting rolls.

The policy was found to affect people with cerebral palsy, autism spectrum disorder, brain trauma, and other intellectual and developmental disabilities, Disability Rights Advocates' Attorney Kara Janssen told LA Times.

Disability and Abuse Project Director Nora Baladerian reportedly called the practices “patently unlawful.”

“Naïve me. I thought in the courtroom the law was followed. ... It wasn’t so. The rights of individuals with disabilities were not being upheld in court,” she told LA Times.

The Judicial Council of California, which manages the state’s courts, said it would cooperate with federal authorities. "We are all committed to the civil rights of all Californians," it said in a statement, according to the Associated Press. The council’s legal director, Thomas Coleman, reportedly said that violations of voting rights were a major part of a system of legal violations and abuses "that make people with disabilities suffer and that have been allowed to continue for far too long."

About 30 states and the District of Columbia have laws that allow limiting the voting rights of people found to be mentally incompetent by a court, although the legal specifics vary. Advocates of these laws say they prevent people with disabilities from being taken advantage of, but critics call it a violation of their human rights.