ICE officials said they are reviewing Abienwi's death to ensure that officials followed policy.
The department has come under heavy scrutiny after President Donald Trump tightened migrant entry rules and refugee detention rules, and implemented stronger enforcement against undocumented migrants.
Watchdogs like the U.S. Inspector General have faulted the border patrol's federal detention facilities, citing dangerous overcrowding that put detainees' health and safety at risk.
Trump administration policy seeks to detain asylees until their case is heard in immigration court. Abienwi, who did not have a criminal record, had been in Customs and Border Patrol Custody for two weeks before being turned over to ICE for long-term detention.
Abienwi left Cameroon due to armed conflicts in his country, where about 500 villages have been destroyed, his family said. He flew to Ecuador and traveled through Colombia, Central America and Mexico before reaching the U.S. border. According to Akongnwi, his brother said he planned to request asylum.
"He wanted to go to the United States, get his documents, start to work, open a business and bring his family, so they can be safe and the kids could go to school," Akongnwi told USA Today.
For decades, Catholic bishops and other leaders have advocated for comprehensive immigration reform.
The bishops have faulted various aspects of Trump administration policy, including its treatment of unaccompanied child detainees, its family separation policy, and its "stay in Mexico" policy wherein would-be asylum seekers are denied entry to the U.S. pending court hearings.
In June Bishop Mark Seitz of El Paso, Texas, whose diocese borders Juarez, Mexico, denounced "a government and society which view fleeing children and families as threats; a government which treats children in U.S. custody worse than animals; a government and society who turn their backs on pregnant mothers, babies and families and make them wait in Ciudad Juarez without a thought to the crushing consequences on this challenged city."
"This government and this society are not well," he said June 26. "We suffer from a life-threatening case of hardening of the heart."
The bishops' concerns about U.S. treatment of migrants pre-date the Trump administration. In a report released in May 2015, titled "Unlocking Human Dignity: A Plan to Transform the U.S. Immigrant Detention System," they charged that detainees receive harsher treatment than criminal defendants and face increased difficulty securing legal counsel and due legal process.
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They advocated reducing the number of detention facilities and recommended community-based case management as a cost-effective and successful model in the legal processing of immigrants.
The report cited attorneys' and pastoral workers' reports of "the sexual abuse of women detainees, women forced to deliver babies in restraints, frequent hunger strikes, suicides, government officials pressuring detainees to abandon their legal claims, and the treatment of severe medical conditions with Tylenol, Advil, and Motrin."