A San Francisco tour operator who handled dead drops of sensitive information on behalf of Beijing’s Ministry of State Security was sentenced Tuesday to four years in prison for spying for China.

Edward Peng Xuehua, a naturalized US citizen, was arrested in Hayward, California, in September for arranging transfers of money and SD cards loaded with stolen data in different locations across the United States on behalf of China’s premier intelligence body.

Peng pleaded guilty in federal district court in Oakland, California, to one charge of illegally acting as an unregistered agent of a foreign government.

The judge sentenced him to 48 months in prison and a $30,000 fine, short of the 10 years and $250,000 fine allowed.

Peng, 56, was exposed by what court filings said was a “double agent operation” targeting the MSS.

The operation led them to Peng, who in 2015 was seen picking up an SD card with US secrets that the double agent, under instructions from her Chinese “handlers,” left inside a book at the front desk of a hotel in Newark, California.