TRENTON, N.J. (CBSNewYork/AP) – New Jersey Gov. Phil Murphy is vowing to investigate his administration’s handling of a state worker’s allegation she was raped by a man who went on to become a senior staffer.

New Jersey Supreme Court Justice Peter Verniero will lead the investigation, Murphy said Monday.

Katie Brennan’s allegations against Albert Alvarez surfaced Sunday in the Wall Street Journal.

Brennan, who currently works as the chief of staff at the state’s Housing and Mortgage Finance Agency, claims Alvarez, a former chief of staff at the state’s Schools Development Authority and Murphy campaign staffer, sexually assaulted her in April 2017.

Alvarez has denied the allegations through his attorney.

Brennan said she called the police and went to the hospital after the attack, in addition to alerting her husband and a friend. She said she tried for about a year to pursue charges against Alvarez, including alerting officials in Murphy’s administration.

“The failure of members of Gov. Murphy’s staff to respond in an aggressive, proactive fashion is unacceptable,” Brennan said in a statement.

Murphy, who succeeded Republican Chris Christie in January, said he was not made aware of the specific allegations until earlier this month, when Alvarez resigned. It’s unclear who exactly in his office found out about the allegations and when.

“I wish we hadn’t made the hire,” Murphy said. “I’m sick to my stomach once I heard what happened obviously.”

Murphy said he learned about the specific allegations on Oct. 2, the day Alvarez resigned.

The governor’s comments came the same day the state attorney general’s office announced it was asking the Middlesex County prosecutor to reopen an investigation into the allegation.

The case was initially investigated by the Hudson County prosecutor’s office in 2017, which closed it without filing any charges. The office says the investigation will now be taken over by the Middlesex County prosecutor’s office because the Hudson County prosecutor, Esther Suarez, knows both Brennan and Alvarez.

Murphy also said he plans to ask the head of the state’s Division of Equal Employment Opportunity and Affirmative Action to review administration policies.

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)