According to court documents, the agents inquired about "three or four Middle Eastern nationals under FBI investigation" who lived in Sterling's apartment complexes.
Subsequently, at the Irolo Street property, Sterling switched to a new type of security gate that required the use of a remote-access garage door opener.
The application for the opener asked tenants to state, among other things, their place of birth and immigration status.
Rhoades called the questions a pretext for learning a tenant's race and national origin.
Fischer said collecting the information was viewed as "as a proper thing to ask in the aftermath of 9/11."
The court rejected Fischer's argument as a "sham," pointing out that Sterling did not circulate a similar questionnaire at any of his other 98 buildings. Nor did he explain, the judge said, "why they suddenly took this action in February 2003 despite having acquired the building in April 2002."
In another issue, tenants claimed that Rochelle Sterling had visited their apartments claiming to be a health inspector or some other government official. A former employee said she accompanied Rochelle Sterling on such visits and was made to document the ethnicity of the tenants.
Rhoades said the purpose of the visits was to gain access to apartments and to harass and intimidate African American and Latino tenants.
Fischer dismissed the former employee's claims as those of a disgruntled worker who has filed a separate lawsuit against Sterling.
Lawyers for tenants submitted a videotape of Rochelle Sterling at a complex, and the judge found that she did tell a tenant that she was a health inspector.
He called the allegations "troubling," and said "impersonating a health inspector may itself be unlawful in other respects." But "there is no evidence in the record that tenants of a particular race or national origin have been targeted for inspection."
The judge did not issue an injunction against the practice.
Sterling denied that he or his wife discriminated against or made derogatory comments about tenants.
"In the 40 years that I have been in the real estate business, I have never before been sued for allegedly violating the Fair Housing Act by discriminating against potential tenants based on race or national origin or otherwise," he said.
The lawsuit was filed on behalf of 12 tenants, one would-be renter, and the Housing Rights Center. An elderly tenant who had been facing eviction has died since the suit was filed. Attorneys expect to select a trial date next month.