Earlier this year, news that Carlos Gregorio Hernández Vásquez, a Guatemalan teenager, had collapsed and died in his Border Patrol holding cell an early morning in May made national headlines. But now, a report from ProPublica raises questions about how federal authorities described and responded to his death.

Video footage from the cell in the South Texas facility shows Hernández, 16, falling onto the concrete floor at 1:36 a.m. After withering for a few minutes, his body becomes still. His lifeless body lays on the floor near a toilet for four hours, when his cellmate wakes up and calls for help.

According to the nonprofit news outlet, a Customs and Border Protection news release following his death claimed that agents discovered the late teen’s body during a welfare check. Since then, the police department in Weslaco, Texas, which first investigated the case, confirmed that it was, indeed, the cellmate who made the discovery.

Additionally, Hernández, who had arrived to the U.S. six days before his death, had a fever that authorities were aware of but failed to provide necessary aid for. During federal processing in McAllen, Texas, a nurse practitioner determined Hernández had a 103-degree fever and the flu. The health professional recommended that authorities have Hernández re-evaluated and hospitalized should his condition worsen. They put him in a cell instead.

The teen’s autopsy revealed that when he passed away he was also suffering from a series of bacterial infections and pneumonia, both usually caused by an untreated flu that worsens over time.

Another aspect in the case that is raising questions is a gap in the footage that Border Patrol gave to local police. ProPublica reports that the video cuts off at around 1:47 a.m. and has a four-hour gap before starting again at around 5:48 a.m. Hernández’s motionless body is in the same position and place. At 6:05 a.m., his cellmate wakes up and goes to the cell door to call on officers outside. Two minutes later, a Border Patrol physician assistant checks the teen’s pulse.

Border Patrol has said that officers made three welfare checks in the hours that the video was cut off.

CBP has not explained the gaps in the footage but said it was “looking into all aspects of this case.”

“While we cannot discuss specific information or details of this investigation, we can tell you that the Department of Homeland Security and this agency are looking into all aspects of this case to ensure all procedures were followed,” a CBP spokesperson told the news site.

Hernández is the sixth immigrant minor to die in federal custody since President Donald Trump took office.