BREAKING: Dallas shooter Joshua Jahn had anti-ICE message on ammo

Special agent in charge of the FBI Dallas Field Office Joseph Rothrock told reporters, "what I can also share with you is that early evidence that we’ve seen from rounds that were found near the suspected shooter contain messages that are anti-ICE in nature."

FBI Director Kash Patel said that one unspent bullet recovered at the scene contained the phrase "anti-ICE" engraved on it. "These despicable, politically motivated attacks against law enforcement are not a one-off. We are only miles from Prarieland Texas where just two months ago an individual ambushed a separate ICE facility targeting their officers. It has to end and the FBI and our partners will lead the these investigative efforts to see to it that those who target our law enforcement are pursued and brought to the fullest extent of justice."

Photos released by the Department of Homeland Security showed bullet holes through the window and into the building’s interior.

In the wake of the shooting, DHS Secretary Kristi Noem wrote, "For months, we’ve been warning politicians and the media to tone down their rhetoric about ICE law enforcement before someone was killed.

"These horrendous killings must serve as a wake-up call to the far-left that their rhetoric about ICE has consequences. Comparing ICE Day-in and day-out to the Nazi Gestapo, the Secret Police, and slave patrols has consequences. The men and women of ICE are fathers and mothers, sons and daughters. They get up every morning to try and make our communities safer. Like everyone else, we just want to go home to our families at night.

"The violence and dehumanization of these men and women who are simply enforcing the law must stop. We are praying for the victims and their families."

Early Wednesday morning, a gunman opened fire on a Dallas ICE facility from a nearby roof, killing one person and injuring others before turning the gun on himself. The shooting occurred as agents were taking detainees into the facility. No members of law enforcement were injured in the shooting.

One witness who was outside the facility described to NBC News hearing a series of gunshots. Arianny Sierra had been outside the facility with her 9-year-old son in the car waiting for her husband who had been at an appointment at the facility. "The shots began at around 6:10 a.m. There were like 20 shots in a row. I sheltered myself under the car with my son," she told the outlet in Spanish.