At noon Tuesday, District 5 Supervisor Ross Mirkarimi will be on the steps of City Hall where he is expected to make an announcement at noon regarding his run for sheriff.

The campaign is not talking about what the announcement will be, only saying that Mirkarimi “will be joined by supporters, and elected officials.”

The affair sounds like it might be the moment when the public finds out who Sheriff Michael Hennessey has decided to endorse as his successor. Mirkarimi previously said Hennessey had encouraged him to run for the seat.

Hennessey wouldn’t say Monday if he plans to officially endorse Mirkarimi at the event, but he said: “I plan to be there.”