A shooter opened fire at a U.S. Immigration and Customs Enforcement facility in Dallas Wednesday morning, leaving one detainee dead and two others wounded. No law enforcement officers were hurt.

The gunman died by a self-inflicted gunshot wound, the authorities said. Three people familiar with the investigation who were not authorized to speak publicly identified the shooter as Joshua Jahn.

Department of Homeland Security officials, along with some state and national leaders, have said the shooting was a targeted attack on law enforcement agents. They have pointed to ammunition the shooter left behind that had the phrase “ANTI-ICE” in blue writing. But officials have not released other details about the shooter or his potential motive, and The New York Times has not independently verified the D.H.S. officials’ claims.

Here’s what we know about the shooting so far.

What Happened in the Attack

The Dallas police responded to a call for assistance at 6:40 a.m. on Wednesday around the ICE field office.

Officials determined after their initial investigation that a gunman, whom they described as a “sniper,” had fired at the ICE building from a nearby rooftop. The attacker fired “indiscriminately,” they said, including at a van where the victims were hit.

One detainee died and two others were in critical condition. Officials have not released the names of the victims, but Mexico’s foreign ministry said in a statement that one of the people injured is a Mexican national.

Following the shooting, Kristi Noem, secretary of the Department of Homeland Security, directed the department to enhance security protocols at ICE facilities nationwide.

What We Know About the Suspect

One of the people familiar with the investigation said Mr. Jahn was 29.

Public records show that he was raised in a suburb of Dallas and, as recently as a few months ago, had been living with his parents, who are from Kansas. The family home is in a rural area north of Dallas and Fort Worth that is rapidly developing.

Mr. Jahn’s political leanings are unclear from what has been uncovered so far. On two Reddit accounts, he wrote mostly about video games, cars, “South Park” and marijuana.

He voted in a Democratic primary in March 2020 in Texas, records show, but he also was registered to vote as an independent in Oklahoma, where his parents own property and where he voted in the 2024 general election.

Mr. Jahn was indicted in 2016 for selling marijuana, records show. A few years later, he was released from court supervision for the charge, and the proceedings were dismissed.

The Site of the Shooting

The Dallas building where the attack occurred is one of 25 ICE field offices across the country. Part of the building is an office used by ICE employees for administrative work. The other part is a processing center for immigrants who have been arrested and are booked into ICE custody.

Detainees who are brought to the building usually undergo fingerprinting, a biometric screening and paperwork. They are then either released or kept in a “hold room” while they await transfer to a long-term facility. The hold room, a waiting area with three or four cells, has held an average of 55 people a day at the Dallas facility. Most detainees spend less than 24 hours in the building before they are moved elsewhere.

Outside the field office, a few dozen community members have been gathering weekly to hold prayer vigils. They have carried signs with messages such as “families belong together.”

Recent Tensions With ICE

Wednesday’s episode was at least the second shooting at an ICE facility in Texas this year.

On July 4, a police officer was shot outside an ICE detention center in Alvarado, Texas, about 28 miles south of Fort Worth. More than a dozen people have been charged in connection with that shooting, which officials have called a coordinated plan to ambush local and federal law enforcement officers. The officer was wounded in the neck but survived.

Three days after the Alvarado shooting, a gunman opened fire at a U.S. Customs and Border Protection station in McAllen, a South Texas border town. Three people, including two officers, were injured.

Homeland security officials have blamed such episodes on “hateful rhetoric” against immigration officers, calling for the end of what they said was a “demonization” of them. President Trump pointed the finger in the Wednesday shooting at “Deranged Radical Leftists,”, calling on Democrats to “STOP THIS RHETORIC AGAINST ICE.”

The shootings came amid months of unrest surrounding Mr. Trump’s escalation of immigration enforcement.

Protests and demonstrations have erupted outside of federal detention facilities nationwide in recent months, leading to confrontations with law enforcement in cities such as Chicago, Los Angeles and New York. Last week, federal officers arrested 11 Democratic elected officials inside a federal building in Lower Manhattan after the officials sought to access the cells where ICE detains migrants.

Hamed Aleaziz, Luis Ferré-Sadurní, Mary Beth Gahan, J. David Goodman, Ruth Graham, Christine Hauser, Amanda Holpuch, Allison McCann, Madeleine Ngo, Aric Toler and Mark Walker contributed reporting.