Video report by ITV News Washington Correspondent Robert Moore
The anguish about the treatment and conditions of America's migrant detention camps continues to grow.
Demonstrations have been held not only at The White House but also at Texas and across the country.
It was given added political heat last week by those photos of a drowned father and daughter.
The report has published photos of overcrowding in the camps and in some cells there is only room to stand and other images show detainees pleading for release.
Inspectors visited five detention centres and ports of entry in the Rio Grande Valley where they found migrants living in squalid conditions, packed into cells with standing room only and sleeping on the floor.
Some migrants had been kept in detention for more than a month and were given wet wipes, as they did not have access to showers.
Members of Congress, who visited the facilities, expressed their outrage at the behaviour of agents who worked for the customs and border protection force.
Alexandria Ocasio-Cortez said: "They put them in a room with no running water and these women were being told by CBP officers to drink out of the toilet."
Another Democrat filmed inside a cell with mothers who have been separated from their children and he said there was one man who shoulders the blame.
"These are the conditions that have been created by the Trump administration, these are the inhumane conditions that folks are facing."
More alarmingly, it has now emerged that current and former border agents are members of a private Facebook group that is engaged in racist threats and used highly derogatory language about the migrants and refugees in their care.
Another commented about a pregnant woman saying: "She's 'HOPING' to cash in on all the perks we SUCKER US taxpayers lavish on them!!!".
The acting head of Homeland Security called the social media exchanges "disturbing and inexcusable".
The news comes as America prepares for Thursday's national July 4 celebrations.
The US President said in a tweet on Wednesday evening if the migrants were unhappy with the conditions, they shouldn't come.