The Afghan national suspected of shooting two National Guard soldiers near the White House on Wednesday once worked with US-backed military forces in Afghanistan, said FBI Director Kash Patel.
"There is confirmation now that the subject had a relationship in Afghanistan with partner forces," Patel told reporters on Thursday.
"We are fully investigating that aspect of his background as well, to include any known associates that are either overseas or here in the United States of America," he added.
The bureau is carrying out "an ongoing investigation of terrorism,” he said.
The FBI, in partnership with several agencies, immediately secured the scene, seized the weapon used, and collected evidence, which is now being analysed at a laboratory, said Patel.
In an expanding nationwide investigation, authorities have executed multiple search warrants across the country, including one at the subject's last known residence in the Pacific Northwest state of Washington, he added.
Authorities have been interviewing witnesses and people related to the suspect as they pursue "anyone and everyone associated with the subject," Patel said.
Suspect background
Jeanine Pirro, the top federal prosecutor in Washington, DC, said the suspect faces multiple felony charges, including three counts of assault with intent to kill while armed and possession of a firearm during a crime of violence.
She said the victims, two West Virginia members of the National Guard who were reportedly sworn into their duty in the capital less than 24 hours before the shooting, are currently getting the "finest medical care" but remain in critical condition.
The prosecutor stated that if either were to pass away, the charges would be immediately upgraded to murder.
Authorities identified the suspected gunman as Rahmanullah Lakanwal, 29, an Afghan national who was taken into custody after Wednesday's attack.
He previously worked with multiple US government agencies, including the CIA, during the war in Afghanistan, according to intelligence officials cited by Fox News.
