Blumenthal said during a Monday news conference that his office is in the process of trying to revoke the pension after Perez was convicted Friday of charges including taking a bribe and attempted extortion.
The mayor said on Friday that he plans to appeal and step down from office. City council members say they anticipate his letter of resignation sometime Monday.
Blumenthal released a statement on Friday saying his office will move forward on the pension matter once Perez is sentenced.
Perez is scheduled to be sentenced Sept. 10 and faces up to 60 years in prison.