A doctor who monitored the woman wrote to the council and said her collapse was genuine.
The rape victim subsequently left the council and said she could not comment. The Whaleoil blog has reported she received $15,000 compensation. Two staff bullied by Dragicevich also resigned and were paid out $300,000 in confidential settlements.
A whistleblower emailed council chief executive Doug McKay two weeks ago alleging the alleged rapist had worked with the woman at the council, and she had been the victim of subsequent bullying by her manager when she complained of trauma. The woman told police she was raped after a few drinks with colleagues after work. No one was charged.
Council spokesman Glyn Walters said the email was sent to adult sexual assault detective sergeant Carl Lewens over a week ago, but Lewens said on Friday he had not received it.
In an emailed statement Mayor Len Brown said he could not comment on individual cases.
"I have been briefed by the chief executive and I am confident any allegation is taken seriously and investigated to ensure the most appropriate outcome."
McKay said: "Bullying is unacceptable. I am confident we have the policies and processes to deal with it."