Homeland Security Secretary Jeh Johnson said Sunday that the sniper who shot and killed five Dallas police officers Thursday acted alone and does not appear connected to a known terror group.

“It was a single shooter, and we do not see any affiliation with a terror network like ISIS or Al Qaeda,” Johnson told “Fox News Sunday.”

Authorities have identified the shooter as Micah Johnson, a 25-year-old black Army veteran, purportedly angry about the two recent incidents -- in Minnesota and Louisiana -- in which police officers fatally shot and killed black men.

Johnson confirmed Sunday that the shooter said that he “wanted to kill white people.”

Dallas Police Chief David Brown said in the aftermath of the shootings that Johnson, who purportedly had received training from a martial arts school on how to be a sniper, “wanted to kill white people, especially white officers.”

Johnson was killed in the standoff that followed the shootings. Three people were purportedly arrested on Thursday night in connection with the shootings, but authorities have not disclosed what role, if any, they had in the incident.

Johnson said the investigation nevertheless continues.

“We’re going to learn more about this [attack] in the coming days,” he said.