The charter bus company Greyhound, which has locations in the city of Brownsville and McAllen, sent a letter to the Department of Homeland Security asking them to test migrants under Border Patrol custody for COVID-19.

In a letter obtained by Channel 5 news, Greyhound's CEO David Leach asks DHS Secretary Alejandro Mayorkas to guarantee migrants that were under border patrol custody test negative for the virus before being allowed onto a Greyhound bus.

The company's president wrote he's concerned about the health of his employees and that of passengers that do not have COVID-19. Other charter bus companies in the Valleys were contacted and said they do not require passengers show they tested negative for COVID-19 - or they simply did not answer calls.

The issue began within the past few weeks after border patrol in the Valley began releasing migrant families with children into the U.S. instead of returning them back to Mexico.

Some migrants with COVID-19 have taken buses to destinations across the country.

In their letter, Greyhound also asked DHS for emergency funding to pay for the costs of sending more buses and personnel to the Valley. So far DHS has not responded to Greyhound's requests, but Secretary Mayorkas has said it is up to local organizations and local governments to test migrants for COVID-19.