Senators Elizabeth Warren and Bob Casey want more federal oversight of the country’s guardianship system following Britney Spears’ emotional testimony about her conservatorship, they wrote in a letter on Thursday.

The lawmakers are calling on the Department of Health and Human Services (HHS) and the Department of Justice (DOJ) to provide information about data the agencies collect on the prevalence of guardianship in the U.S, any efforts the agencies have made to protect people under guardianship and ways Congress can improve the federal collection of guardianship data.

“Ms. Spears’ case has shined a light on longstanding concerns from advocates who have underscored the potential for financial and civil rights abuses of individuals placed under guardianship or conservatorship,” Warren and Casey wrote in a letter shared exclusively with TIME.