EXCLUSIVE — A senior Senate Republican is pushing Sen. Bernie Sanders (I-VT) to investigate the sexual abuse of unaccompanied migrant children in federal custody following a Justice Department lawsuit against a childcare contractor.

Sen. Bill Cassidy (R-LA) sent Sanders, the chairman of the Senate Health, Education, Labor, and Pensions Committee, a letter Thursday afternoon in which he asked to convene a hearing to examine how the Department of Health and Human Services Office of Refugee Resettlement had allowed “despicable acts of abuse” toward children under its care.