According to a criminal complaint made public Monday, a Hayward man has been arrested and charged with espionage after allegedly working over multiple years as an agent for Chinese intelligence.

The man, Xuehua "Edward" Peng, 56, operated tours for Chinese visitors and students, and he was taken into custody Friday. U.S. Attorney David L. Anderson said in a Monday press conference that Peng had engaged in "a combination of age-old spycraft and modern technology" during six trips he made between the San Francisco Bay Area and Columbus, Georgia between 2015 and 2018.

"The charges announced today specifically regard the use of an American citizen to remove classified national security information from the United States to the People's Republic of China," Anderson said. "An American citizen acted as a secret agent of the People's Republic of China against the United States here in the Northern District of California."

As the Associated Press reports, Peng's m.o. was to rent hotel rooms to use as "dead drops" where he would leave $20,000 and then have an exchange with an FBI agent who was supposedly working as a double agent for China. The agent would collect his or her cash and leave behind SD cards containing seemingly important, purportedly classified national security information about U.S. Peng is then accused of traveling to Beijing on multiple occasions where he would hand over the SD cards to officials with China's Ministry of State Security.

Per the New York Times, "At a moment of trade and military tensions with Beijing, the indictment [of Peng] is just one more potential irritant, but also a brief view into the constant, low-level intelligence war underway each day."

Peng's arrest comes after a multi-year investigation, as CBS News reports, and Peng was arrested at his home in Hayward on Friday. If convicted, he could face up to 10 years in prison for acting as a foreign agent.

Peng became a naturalized U.S. citizen in 2012 after arriving in the Bay Area on a temporary business visitor visa in 2001. He holds a license as a registered acupuncturist in California.

He is due in court on Wednesday and he is currently in custody in San Francisco being held without bond, per the AP.