A staff member for a Democratic California lawmaker remains in federal custody after immigration authorities arrested him at a Las Vegas airport during a targeted enforcement operation.
Ho-Yin Mo, a field representative for California Assemblywoman Catherine Stefani, was arrested by federal agents at Harry Reid International Airport on Sept. 17.
Mo, who is originally from Hong Kong and previously worked as a television journalist in San Francisco, was later taken to the Nevada Southern Detention Center in Pahrump.
The Department of Homeland Security said Mo legally entered the U.S. on Jan. 13, 2020.
According to DHS, however, his authorized stay expired on May 15 of that year and he remained in the country afterward.
“Mo lawfully entered the U.S. on a temporary basis but illegally overstayed his welcome,” DHS said.
The department also pushed back against arguments that Mo’s employment authorization means he currently has lawful immigration status.
“Work authorization or a pending application do NOT confer legal status in the United States,” DHS said.
Mo’s attorney, Kevin Lo, has provided additional details about the case.
Lo said Mo applied for asylum in 2023 and that the application remains pending.
He also said Mo has a valid employment authorization document that allows him to legally work in the United States while his asylum case is being considered.
Employment authorization and immigration status are separate legal questions.
Some immigrants with pending applications are allowed to work even while their broader immigration status remains unresolved.
Mo has not been publicly accused of committing a criminal offense in connection with the arrest.
His detention instead stems from the alleged immigration violation and resulting removal proceedings.
Stefani has publicly called for Mo’s release.
“My message today is simple: I am respectfully calling for Ho Yin Mo’s release as soon as possible,” she said.
Stefani described Mo as an important member of her district office.
She said he helps constituents navigate government programs and services.
According to Stefani, Mo assists residents with issues involving health care coverage, child care, food assistance and other government benefits.
He also serves as a liaison to Chinese-American communities within the district.
“Our whole community eagerly awaits Ho Yin’s return to his home and his job where he is loved and adored,” Stefani said.
Mo joined Stefani’s district office in January 2025.
Before working for the California Legislature, he was involved in Asian American and Pacific Islander outreach during former San Francisco Mayor London Breed’s unsuccessful 2024 reelection campaign.
Mo had previously worked in broadcasting.
He served as an anchor and reporter for KTSF Channel 26, a Chinese-language television station serving the San Francisco Bay Area.
That work made him a recognizable figure among parts of the region’s Chinese-speaking population.
Stefani represents California’s 19th Assembly District.
The district includes western San Francisco and northern San Mateo County.
She previously served on the San Francisco Board of Supervisors before joining the state Assembly.
Federal officials have defended the arrest despite Mo’s employment with a state legislator.
“No one is above the law, not even the California legislature and its staff,” First Assistant U.S. Attorney Bill Essayli wrote on social media.
DHS also tied the case to the Trump administration’s broader immigration enforcement efforts involving airports and domestic travel.
The department said the administration has changed policies that previously allowed some people without lawful immigration status to travel domestically while their cases remained unresolved, per the Conservative Brief.
“This administration is working diligently to ensure that aliens in our country illegally can no longer fly unless it is out of our country to self-deport,” DHS said.
The Transportation Security Administration has also tightened identification requirements for some travelers without conventional identification documents.
Mo’s case now centers on a key legal distinction.
Stefani and Mo’s attorney emphasize that he has federal authorization to work and a pending asylum application.
DHS maintains that neither of those facts, by themselves, establishes lawful immigration status.
