Less of a specific incident and more of the eventual outcome of a number of factors, as of June 2019, there have been 24 examples of deaths while in ICE custody. Those who advocate for unrestricted immigration have complained of awful conditions within a system that is unable to handle the influx the incredible numbers of people flooding into it. Those who advocate for a strict policing of immigration law point the finger back at the people refusing to wait their turn like everyone else.
Either way, ICE has been detaining nearly twice as many people as they had been during the Obama administration. Because of that influx, substandard conditions run rampant through more than 200 detention centers in the country. Whether or not that has always been the case is up for debate; illegal immigrants have always died in US custody, 32 in 2004 and 12 in 2016.