Katie Brennan spent more than a year trying to get authorities to take action against the man she accuses of sexually assaulting her. Finally, she emailed New Jersey Gov. Phil Murphy.

Ms. Brennan, chief of staff at the state’s housing agency and a former volunteer for the governor’s campaign, first called the police in April 2017, one day, she said, after a campaign staffer allegedly forced himself on her. After months of investigation, the county prosecutor’s office declined to file charges against her alleged attacker, saying it didn’t think a jury would convict him. She turned to state law enforcement and high-ranking members of the Murphy administration. Nothing changed.

Finally, the 31-year-old Jersey City resident, who said she turned down a $15,000 settlement offer from her alleged assailant if she signed a nondisclosure agreement, emailed Mr. Murphy and first lady Tammy Murphy directly.

She didn’t explicitly mention the alleged assault in her June 2018 email, but asked to speak with the governor or his wife about a “sensitive matter” that had happened during the campaign. The governor responded within the hour and said he was looping in staff to arrange a time.

“Hang in,” the governor wrote to Ms. Brennan in the email, which was reviewed by The Wall Street Journal. “We are on it.”

A meeting with the governor was never scheduled. And months later, the man, Albert J. Alvarez, was still working for the state, as chief of staff at the New Jersey Schools Development Authority. Mr. Alvarez resigned his position Oct. 2, the same day the Journal emailed him for comment.

“At each turn, I’ve just felt so disappointed,” Ms. Brennan said in an interview. “I tried everything. And none of it worked. If I can’t get any justice, I just don’t seriously know who can.”

“At each turn, I’ve just felt so disappointed. I tried everything. And none of it worked. If I can’t get any justice, I just don’t seriously know who can.”

— Katie Brennan

Mr. Alvarez’s attorney, John Hogan, said his client “absolutely, positively denies these allegations of sexual assault.” He declined to comment further on any aspect of Ms. Brennan’s account. Neither Mr. Alvarez nor his attorney responded to additional attempts to reach them by phone or to an email with detailed questions.

After his resignation, Mr. Alvarez was named in local and national press reports about the allegation. Ms. Brennan spoke publicly about the alleged assault for the first time for this article.

New Jersey Republicans have called for an investigation into Mr. Alvarez’s hiring, and the state Senate’s Democratic leadership said in a statement they were disturbed by the allegations.

On Friday, Gov. Murphy’s spokesman said his office received a separate accusation on Thursday against Mr. Alvarez. The accusation, which was referred to the New Jersey attorney general’s office, concerned an incident that allegedly occurred in 1999 or 2000, the spokesman said. Neither Mr. Alvarez nor his attorney responded to a request for comment on the allegation.

This story continues in the Wall Street Journal.