The Housing Authority of the City and County of San Francisco told commissioners that the San Francisco City Attorney’s office investigated allegations of illegal rent collection by a contractor employee and found no evidence to substantiate those claims. The update came during the chief executive officer’s report at the Authority’s public meeting.

The CEO said the City Attorney’s memorandum concluded “allegations of illegal rent collection by EBMC employee, Lance Wittenberg, cannot be substantiated,” and that investigators could not secure cooperation from people who claimed to have paid the employee. The Authority also said the City Attorney interviewed ‘‘over three dozen witnesses’’ as part of its review and shared the memorandum with the board.

Why it matters: the allegations had raised concerns about possible exploitation of vulnerable people in vacant buildings slated for demolition. Housing Authority leaders told the commission that the claims were primarily made by nonlease holders — people unlawfully occupying units — and that the agency is troubled by separate reports that three nonlease holders said they had been extorted by unknown men under threat of violence.

Authority response and next steps: the CEO said the Authority has referred the matter to the City Attorney and is working with law enforcement and other agencies to investigate reports of threats and to prevent exploitation. The CEO urged anyone with knowledge or evidence to contact the City Attorney’s office at cityattorney@sfcityatty.org or call (415) 554-3977.

What the City Attorney memo did not find: according to the CEO’s report, investigators found no evidence that the named EBMC employee engaged in illegal rent collection. That finding does not, the Authority said, diminish the seriousness of reports that people living in vacant units experienced threats or were targeted for extortion; the Authority said it will continue partner investigations and outreach.

The meeting record: commissioners thanked staff and the City Attorney’s office for the investigation. The Authority said it will continue working with police and the City Attorney’s office to ‘‘root out this behavior’’ and to keep uninhabitable units unoccupied for safety reasons. The CEO’s statement and the City Attorney reference were read into the record during the CEO’s report.