Attorneys for Yazmin Juárez submitted the claim against multiple agencies Tuesday. Juárez 's 1-year-old daughter, Mariee, died in May.
Juárez 's lawyers said Mariee developed a respiratory illness while she and her mother were detained at the South Texas Family Residential Center in Dilley, Texas. They accused U.S. Immigration and Customs Enforcement of releasing the pair while Mariee was still sick.
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The girl died six weeks later in Philadelphia.
Washington-based law firm Arnold & Porter said it will file a lawsuit if the government doesn't settle its claim. R. Stanton Jones, a lawyer at the firm, said the government has six months to respond before his firm can file suit.
"Having made the decision to jail small children, the U.S. government is responsible to provide living conditions that are safe, sanitary and appropriate," Jones said.
A spokesman for U.S. Customs and Border Protection said the agency wouldn't comment on pending litigation. Other agencies didn't immediately respond to messages.
Jones has also submitted a $40 million claim against the city of Eloy, Arizona, which officially operated the Dilley detention facility under a "pass-through" agreement with ICE and the private prison company CoreCivic. ICE and CoreCivic replaced its agreement with Eloy in September with an arrangement made with the city of Dilley.
Advocates have long complained that medical care in Dilley is substandard and that detaining families damages their mental health. ICE has defended the care it provides at Dilley, saying detainees have access to medical professionals.
Dilley is now being used to detain mothers and children, some of whom were reunited in detention after being separated earlier this year under Trump administration policy.