A handwritten note recovered after a deadly shooting in Dallas detailed the suspect’s desire to inflict “real terror” on US immigration agents, the head of the FBI has said.

One person was killed and two people were critically injured after a gunman opened fire at an Immigration and Customs Enforcement (ICE) field office in Dallas, Texas, on Wednesday.

All three victims were in a transport van outside the facility at the time, the Department of Homeland Security said in a statement.

Several more people were injured before the gunman took his own life, officials said.

Image:
Joshua Jahn has been named as the suspected gunman

FBI director, Kash Patel, said the agency had seized devices and processed “writings” obtained at the scene and in the suspect’s home since the attack.

A handwritten note recovered read: “Hopefully this will give ICE agents real terror, to think, ‘is there a sniper with AP rounds on that roof?”

The FBI previously said the suspect left a bullet casing engraved with the phrase “ANTI-ICE” at the scene.

Mr Kash said in a post on X: “While the investigation is ongoing, an initial review of the evidence shows an ideological motive behind this attack.”

One of the bullet casings was engraved with 'ANTI ICE'. Pic: Kash Patel/X
Image:
One of the bullet casings was engraved with ‘ANTI ICE’. Pic: Kash Patel/X

Acting ICE Director Todd Lyons told Sky News partner NBC that ICE agents pulled some of the detainees out of the line of fire.

“The shooter was just shooting at random vehicles inside,” Mr Lyons said

“They were still hit inside the vehicle. You know, there were some brave men and women on the ground that went into those vans, pulling those detainees out while they were under fire.”

According to the FBI, evidence recovered so far shows a high level of planning ahead of the shooting, including searches of buildings belonging to the Dallas County Office of Homeland Security and Emergency Management.

The shooting happened at an ICE field office in Dallas. Pic: Reuters
Image:
The shooting happened at an ICE field office in Dallas. Pic: Reuters

Officials have not yet disclosed the identity of the victims.

US Homeland Security Secretary Kristi Noem identified the gunman, in a Fox News interview, as Joshua Jahn, 29.

Ms Noem said he had fired the bullets from a nearby rooftop.

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Mr Jahn’s older brother, Noah Jahn, who lives around 30 miles north of Dallas in McKinney, said he was not aware his brother held any negative feelings towards ICE.

He said: “I didn’t know he had any political intent at all.”

The shooting comes at a time of heightened tension in the US following the assassination of right-wing influencer Charlie Kirk.

Mr Kirk, a close ally of President Donald Trump, was shot dead by a sniper while speaking at an event in Utah on 10 September.

Tyler Robinson, 22, has been charged with the murder of Mr Kirk.