Notes written by the person suspected of opening fire on an immigration facility in Texas indicate he was targeting ICE agents and did not intend to harm detainees, acting US attorney for the Northern district of Texas Nancy Larson said. One detainee was killed and two others critically injured after a suspected sniper opened fire at an Immigration and Customs Enforcement (ICE) centre in Dallas on Wednesday, officials said.

Speaking at a news conference on Thursday, Ms Larson identified the shooter as 29-year-old Joshua Jahn, adding that notes he had written had been found at his home. She said he intended to 'maximize lethality against ICE personnel and to maximize property damage at the facility'.

'He hoped to minimize any collateral damage or injury to the detainees and any other innocent people,' she added. 'It is clear from these notes that he was targeting ICE agents and ICE personnel.'

The victims have not yet been identified. FBI director Kash Patel said earlier that evidence 'to this point indicates a high degree of pre-attack planning'. Patel mentioned one of the handwritten notes found said: 'Hopefully this will give ICE agents real terror, to think, 'is there a sniper with AP rounds on that roof?'

Larson noted that the shooter 'very likely acted alone' and added that that morning gunshots sprayed the length of the building, the windows, and law enforcement vans that were in the sallyport area. She emphasized that the notes included a 'gameplan of the attack', describing ICE employees as 'people showing up to collect a dirty paycheck'.

Larson asserted that the shooter hoped his actions would 'terrorize ICE employees and interfere with their work'. 'What he did is the very definition of terrorism,' she remarked.

No evidence was found of membership in any specific group, and the shooter did not mention any specific government agency other than ICE, she said, but he did express his hatred for the federal government. She also praised ICE and other federal agents who worked under fire to remove detainees from vans and get them to safety.

FBI special agent Joe Rothrock described it as a 'targeted, ambush-style attack on law enforcement', stating that the shooter 'specifically intended to kill ICE agents' and fired at transport vehicles carrying ICE personnel, federal agents, and detainees. 'Jahn also acknowledged the potential for other casualties,' Rothrock said.

Marcos Charles, ICE field office director of enforcement and removal operations, condemned the violent rhetoric against ICE, asserting that 'in contrast to those who would demonize our men and women, yesterday our brave officers ran back into danger to save the detainees while shots were still being fired.'