NYTimes's update has details about the facililty:
https://www.nytimes.com/2025/09/24/us/dallas-texas-ice-facility.html?smid=url-share
The building that was targeted by a gunman early this morning is the U.S. Immigration and Customs Enforcement Dallas field office, a facility that is part office building and part processing center for immigrant detainees. The majority of the building is used by ICE employees for administrative work, with desks and cubicles for deportation officers. Some immigrants who are not detained will also appear here for things like check-in appointments or to post bond.
The other part of the building is used to process detainees who have been arrested and are being booked into ICE custody. The shooter, a sniper who opened fire from a nearby rooftop, fired indiscriminately, including at a van in an entrance area on the side of the building where the victims were shot, the Department of Homeland Security said in a statement.
An immigrant detainee refers to a person in the custody of either ICE or U.S. Customs and Border Protection. Detainees at the Dallas ICE field office, where the shooting occurred, are typically in the process of being booked into ICE custody or transferred elsewhere. Detainees are not housed at this building long term.
Detainees who are brought to the building will undergo fingerprinting, a biometric screening and any necessary paperwork. After, they will either be released or be held in the buildingβs βhold room,β a small waiting area with three or four cells where immigrants who are awaiting transfer are held. Most detainees will spend less than 24 hours in the building.
More than 8,400 people have spent time in the hold room at the Dallas ICE field office since President Trump took office, according to data from the Deportation Data Project through July. The hold room has held, on average, about 55 people a day who are awaiting transfer to a long-term ICE detention facility.
Eric Folkerth, the senior pastor at a Methodist church in Dallas, spends time outside the building regularly as a leader of an interfaith prayer vigil that takes place there every Monday. The vigil is typically silent, Rev. Folkerth said, and attendees hold signs demanding justice for the detainees. Rev. Folkerth condemned the shooting. From the beginning, he said, his group has prayed both for immigrants and for ICE agents, βthat they not cause moral or physical harm to themselves and others.β