A U.S. citizen named Alexei Saab allegedly performed surveillance work at various U.S. landmarks for the jihadist terrorist group Hezbollah from 2000 to 2005 and was “ready to attack Americans at popular locations if Iran was attacked by the U.S.,” Assistant U.S. Attorney Samuel Adelsberg said in a federal court on Monday.

“By day, Saab was a software engineer working for technology companies,” Adelsberg said. “By night, he was ‘a terrorist and spy’ scoping out potential terrorism targets in New York, Boston, [and] Washington, DC.”

Saab, 45, is a resident of Morristown, New Jersey. He gained U.S. citizenship in 2008 after first entering the country in 2000 with a Lebanese passport. The U.S. Department of Justice (DOJ) announced extensive terrorism-related charges against Saab, accusing him of working as a member of Hezbollah’s external operations unit, known as the Islamic Jihad Organization, from 2000 to 2005.

Professional engineer Saab surveilled several New York City landmarks as part of his reconnaissance work, including the Statue of Liberty, the Empire State Building, Times Square, and Rockefeller Center, according to the indictment. He additionally studied the layouts of NYC-area tunnels, bridges, and airports. Saab allegedly relayed information to the IJO that highlighted perceived structural weaknesses or “soft spots” of the sites.

Hezbollah allegedly planned to use this information to determine how to maximize destruction should they plan a terror attack.