The gunman who shot three migrants at an immigration centre in Texas before killing himself was once arrested for dealing marijuana.

Joshua Jahn was named by US media as the sniper who killed at least one migrant before turning the gun on himself at an immigration and customs enforcement (ICE) facility in Dallas, Texas, on Wednesday.

The 29-year-old from Fairview, Texas, was perched on top of an immigration lawyer’s office 218 yards from the ICE facility when he opened fire.

He was the son of Democrat and Republican parents but family members said Jahn showed little interest in politics.

However, bullet casings found next to his body were scrawled with the words “anti ICE”, prompting figures in the Trump administration to condemn the attack as an act of radical Left-wing violence.