Four women claim in a civil lawsuit that a high-ranking Qatari diplomat in the United States, and his family, forced them to work around the clock for little pay while enduring emotional abuse and — according to one woman — sexual assault.

The human trafficking lawsuit was filed March 25 in U.S. District Court in Washington, D.C., against Essa Mohamed Al Mannai, Qatar’s second-highest ranking diplomat in the United States. The case has reopened debate over a problem that has vexed U.S. government agencies charged with making sure foreign officials, who enjoy the cover of diplomatic immunity, still obey U.S. laws and labor standards.

The lawsuit has also renewed criticism of the U.S. State Department, accused by human rights activists of not doing enough to address persistent complaints of abuse by visiting foreign officials.

Each year, about 3,500 visas are issued to domestic workers employed by diplomats and officials at international organizations like the World Bank. Between 2000 and 2008, 42 cases of alleged abuse of these laborers were discovered by the federal Government Accountability Office, which surveyed several agencies and non-governmental organizations.