Warning: This article contains an image that some may find distressing
Oscar Alberto Martínez Ramírez and his nearly two-year-old daughter Valeria were found in Matamoros, Mexico on Monday, after they drowned trying to cross the river to Brownsville, Texas.
Martinez' wife, Tania, told Mexican authorities she watched her husband and child disappear in the strong current.
Shortly after the image was released, the acting head of US Customs and Border Protection (CBP) said he was resigning amid an uproar over the discovery of migrant children being held in pitiful conditions at one of the agency’s stations in Texas.
John Sanders’s departure deepened the sense of crisis and added to the rapid turnover inside the agencies responsible for enforcing as the US deals with record numbers of migrant families coming across the southern border.
In a message to employees, Mr Sanders said he would step down on July 5. He did not give a reason for leaving.
Six children have died since September after being detained by border agents.
“Although I will leave it to you to determine whether I was successful, I can unequivocally say that helping support the amazing men and women of CBP has been the most fulfilling and satisfying opportunity of my career,” he said.
Hours after Mr Sanders’s departure became public, two officials said that he was being replaced by Mark Morgan, who was named acting director of US Immigration and Customs Enforcement just last month.
In an interview last week, Mr Sanders blamed the problems in detention on a lack of money and called on Congress to pass a $4.5billion (£3.55 billion) emergency funding bill to address the crisis.
The House approved the legislation on Tuesday night, setting up a showdown with the Senate where Republican leaders plan approval of a different, bipartisan bill this week that does not offer as many protections and services for migrants.
At the White House, Mr Trump said that he did not ask for Mr Sanders’s resignation — adding that he does not think he has ever spoken to the man — but that he is “moving some people around into different locations” amid the crisis.
While activists welcomed Mr Sanders’s departure, Mr Trump defended US border authorities, saying: “The laws are so bad and the asylum rules and laws are so bad that our Border Patrol people, who are so incredible, aren’t allowed to do their jobs.”
The unprecedented surge of migrant families has left US immigration detention centres severely overcrowded and taxed the government’s ability to provide medical care and other attention.
On Sunday, two babies, a toddler and a woman were found dead on the Texas side, overcome by the sweltering heat.
The Trump administration has faced a barrage of criticism in recent days over conditions inside the Border Patrol facility in Clint, Texas, first reported by The Associated Press: these include inadequate food, lack of medical care, no soap and older children trying to care for toddlers.
An official from Customs and Border Protection said on Tuesday that the majority of the roughly 300 children detained at Clint last week had been moved to facilities operated by the Office of Refugee Resettlement.
But around the same time Mr Sanders announced his resignation, his agency said officials had moved more than 100 children back to the station.
CBP is the agency that apprehends and first detains migrant parents and children crossing the Mexican border.
CBP’s facilities at the border were almost all built when most people crossing into the US illegally were single adults.
Now, the agency is apprehending tens of thousands of parents and children weekly. It recorded 84,500 apprehensions of adults and children travelling together in May.