Montana Gov. Steve Bullock (D.) kept sexual harassment claims against a former aide secret, allowing the aide to find new employment where he again came under fire for sexually harassing subordinates.

Bullock hired Kevin O'Brien in 2015, when Bullock served as chairman of the Democratic Governors Association. O'Brien left the post after an investigation found a woman's accusations of sexual harassment credible, the New York Post reports..

O'Brien next applied to serve as deputy chief of staff to New York City Mayor Bill de Blasio (D.) in early 2016. As part of the hiring process, New York's Department of Investigations reached out to the applicant's former places of employment. The department contacted O'Brien's former offices as required, according to New York City Hall spokesman Eric Phillips. It "received confirmation of title and work dates and no adverse information," Phillips said. O'Brien got the job.

O'Brien served as de Blasio's deputy chief of staff until early 2017, and he was briefly promoted to acting chief of staff. He became a senior adviser to the mayor after his reelection, earning $220,652.

In March 2018, investigators confirmed several accusations of sexual harassment against O'Brien. He resigned and admitted to wrongdoing. "There’s no excuse for what I’ve done. I’m embarrassed and ashamed. No one deserves to be treated that way. I’ve apologized to the people I’ve hurt and will continue to do so because I am truly sorry," he told the New York Times.

Bullock's office admitted it had not warned de Blasio's office about O'Brien's behavior and the investigation. Ronja Abel, a spokeswoman for Bullock, explained the governor thought the firing would have been enough. "Gov. Bullock fully agreed with the decision to end Mr. O’Brien’s employment with the DGA," she said. Bullock "expected that having been held accountable for his actions, Kevin would not repeat this behavior."

De Blasio ripped into O'Brien's conduct and the lack of disclosure from Bullock's office. "The whole thing is disgusting and it makes me tremendously angry that someone lied to us," he said.

Bullock is considering a run for the Democratic nomination for president in 2020.