Two men tied to a federal investigation that also included searching Oakland Mayor Sheng Thao's home are linked to a recycling company that contracts with the city.
The men are David Duong, who is the CEO of California Waste Solutions, and his son, Andy Duong, who have deep ties to both city politics and city business.
"I understand the Duong family have been very supporting of causes that have created opportunities to create a more robust and prosperous economy for all of us to thrive in," said Jennifer Tran, president of the Vietnamese Chamber of Commerce and Congressional candidate. "Like many of our families, the Duong family is a family who arrived here as refugees with nothing and have been able to piece together opportunities to be able to create this really impressive business called California Waste Solutions."
FBI and postal inspectors searched the headquarters of Oakland's recycling collector and the homes of David Duong and Andy Duong as part of the same operations that included a search of Thao's home.
While it is unclear what federal investigators were after, NBC Bay Area is learning more about California Waste Solutions and the Duong family.
The Duongs and their company have contributed hundreds of thousands of dollars to political candidates on both sides of aisle over the years, including donations to the mayor. Their social media pages also show them hobnobbing with politicians and business leaders.
The Vietnamese Business Association, which David Duong chairs, organized a trip to Vietnam last year that Thao and members of the Port of Oakland took part in.
The Port said it reimbursed the association for trip expenses for its four employees and for the mayor.
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The Duongs and Thao have been the subject of an Oakland Political Ethics Commission investigation for alleged campaign contribution violations.
Tran acknowledges her father has been questioned as part of that probe, and that her congressional campaign has received $3,300 contribution from David Duong. Tran said she hopes the federal probe leads to accountability and transparency.
"I think that anyone, including the Duongs, including the donors of other campaigns, needs to definitely be assessed," she said. "But also given a fair trial."
NBC Bay Area was unable to reach the Duongs on Friday for comment.