Dozens of Federal Bureau of Investigation agents this week scoured two residents linked to Mexican businessman Jose Susomo Azano Matsura and seized electronics and financial records.
KPBS has identified Azano as the "foreign national" named in a federal complaint unsealed Tuesday that alleges he illegally contributed to San Diego campaigns.
A source familiar with the Wednesday raids told KPBS that a total of 50 FBI agents descended on two Coronado homes tied to Azano, one on Green Turtle Road and the second on Buckaneer.
The source said agents spent eight hours at the residences sifting through financial records such as check stubs, searching vaults and safes and going through smart phones and computers.
Azano, his wife, mother-in-law and a cook were at one of the homes at the time.
The source described the search as amiable, adding that the agents were respectful.
Federal officials believe half a million dollars of Azano's money was illegally funneled to San Diego mayoral and congressional candidates in the last two years. As a Mexican national, it is illegal for Azano to finance U.S. campaigns with foreign money.