Human traffickers used fiancé and work visas to bring dozens of victims to the United States, exploiting a lack of data sharing between immigration offices within the Department of Homeland Security, according to the agency's internal watchdog, reports the New York Times.

In a report released on Monday, investigators found that from 2005 to 2014, 17 of the 32 known traffickers they examined used the visas to bring in victims who were exploited for either forced labor or prostitution. In addition, the report found that 274 suspected traffickers successfully petitioned federal officials to bring 425 family members or fiancés into the United States.

The report, by the Department of Homeland Security's Office of the Inspector General, comes as Congress is beginning to examine the visa program after the mass shootings in San Bernardino, Calif., that left 14 people dead and 22 wounded.

Tashfeen Malik, one of the attackers, was granted entry to the United States under a K-1 visa, also known as a fiancé visa. Her husband, Syed Rizwan Farook, was an American-born citizen. Both died in a shootout with the police.