California federal prosecutor Aiseli strictly handles the Chinese espionage case and once handled the surveillance case of Tsai Ing-wen’s visit to the United States.

Assistant U.S. Attorney Bill Essayli of the U.S. Attorney's Office for the Central District of California, who announced on

In 2023, Tsai Ing-wen, then President of Taiwan, led a delegation to embark on the "Partners in Democracy and Common Prosperity Tour", passing through California and visiting the Reagan Library. Sun Yaoning, a Chinese man, was instructed by Chinese officials to closely monitor Tsai Ing-wen's itinerary, whereabouts and interactions with the masses during her transit in Southern California, and sent photos and real-time updates taken at the scene back to officials of the Chinese Consulate General in Los Angeles. This case was handled by Aceli.

In addition, Sun Yaoning also monitors Taiwan independence, Tibetan independence, Xinjiang independence groups and Falun Gong for China. In February 2026, Sun Yaoning was sentenced to 4 years (48 months) in prison by the Federal Court for the Central District of California.

Aceli was born in Corona, California in 1985; he graduated from California State Polytechnic University, Pomona, and received a doctorate in law from Chapman University. He first served as a deputy prosecutor in the Riverside County District Attorney's Office; from October 2014 to February 2018, he worked as a prosecutor in the same federal prosecutor's office, specializing in violent, organized crime and white-collar crime. He once participated in the investigation team of the 2015 San Bernardino terrorist attack.

Aiseli, a Republican, was elected to the California House of Representatives (63rd District) in 2022. Appointed as an interim federal prosecutor by the Trump administration in April 2025; he resigned before the expiration of his 120-day term and was immediately appointed as the first assistant by Attorney General Bondi so that he could continue to preside over the largest federal prosecutorial district in the United States (seven counties including Los Angeles) as an "acting prosecutor".

When the U.S. Department of Justice was sentenced in the Sun Yaoning case, it emphasized that the case was part of a counterattack against foreign governments engaging in illegal agent activities and intelligence collection in the United States. Now that the case of Zhang Wanying, who was monitoring President Lai's family, has been uncovered again, it shows that the Chinese government's espionage methods in the United States are becoming increasingly rampant, which is tantamount to an open threat. The rapid and successful arrest by U.S. prosecutors and the FBI is also an effective counterattack against China's illegal cross-border crimes.