Washington — The Afghan national charged with planning an Election Day terror attack was previously employed in a security role in Afghanistan by the CIA, CBS News has confirmed.

Nasir Ahmad Tawhedi, who was arrested Monday in Oklahoma City, is accused of planning the attack on behalf of ISIS.

Tawhedi along with unnamed co-conspirators — including a juvenile who is Tawhedi's brother-in-law — took several steps to carry out the attack in the U.S., including selling their family home and their belongings and were in the process of relocating their family abroad and purchasing firearms and ammunition, according to a criminal complaint unsealed Tuesday.

Twenty-seven-year-old Tawhedi traveled to the U.S. in September 2021, days after the U.S. withdrew from Afghanistan. He was initially paroled into the U.S. on Sept. 9, 2021, and currently has a pending application for lawful permanent resident status based upon an approved petition for a Special Immigrant Visa, according to a Department of Homeland Security official.

The U.S. offers Special Immigrant Visas to individuals who worked with its armed forces or under chief of mission authority as a translator or interpreter in either Iraq or Afghanistan, according to the State Department.

"Every Afghan being resettled in the United States undergoes a rigorous screening and vetting process no matter which U.S. government agency they worked with," a U.S. official told CBS News. "That process includes checking against a full range of relevant U.S. records and holdings."

The CIA declined to comment. NBC News first reported Tawhedi's employment at the CIA.

Federal investigators allege that Tawhedi searched for access to surveillance and security cameras located in Washington, D.C., and checked webcams showing the White House and Washington Monument in late July. They also believe Tawhedi was seeking out places in which gun laws were more lax.

Tawhedi and his brother-in-law received two AK-47 rifles on Monday, shortly before their arrest, according to the criminal complaint.

In an interview with investigators after his arrest, Tawhedi said they had purchased the weapons to carry out an attack on Election Day and target large gatherings of people, during which they "expected to be martyred," the complaint says.

Tawhedi, who remains in custody, is scheduled to appear in court on Oct. 17 for a detention hearing.

contributed to this report.