Rep. Ilhan Omar, D-Minn., could face deportation because she "married her brother" as part of an alleged immigration scheme, Department of Homeland Security Markwayne Mullin said on Thursday. 

Mullin made the remark at the GOP midterm convention in Dallas while discussing the "ongoing" investigation into the congresswoman with conservative podcaster Benny Johnson, the New York Post reported. 

“We know that she married her brother to try to bring him to the United States,” Mullin told Johnston, adding that Omar's ex-husband lives in London. 

Mullin explained that lying about certain things on an immigration application can result in deportation, and there's no expiration for that. 

The investigation may turn up "illegal activity," which could result in Omar being deported, Mullin suggested. He cautioned that the case is still being investigated and insisted it's not politically motivated. 

Omar became a naturalized U.S. citizen in 2000, when she was 17 years old, and she has vehemently denied marrying her brother.