Former Secretary of Public Safety and Suffolk County Sheriff Andrea Cabral said Thursday that something in the culture of the Massachusetts State Police needs to change.

On Wednesday, the former president of the state police union, Dana A. Pullman, was arrested for allegedly taking bribes from a lobbyist and using the union’s money for his own personal expenses. Federal prosecutors accused Pullman of taking thousands of dollars from the union to pay for expensive dinners, gifts and a new car for himself. The arrest came about a year after three former state troopers were arrested last summer for claiming to work overtime shifts that never occurred.

Read more: Former State Police Union Head And Lobbyist Arrested, Charged With Misusing Union Funds

Cabral praised the work of a majority of the state police force, but said that her own experience as secretary of public safety showed her how challenging it can be to change the culture of the institution. In particular, Cabral said that she had to overcome a decades-long culture of hiring predominantly white troopers to improve diversity within the state police.

“It was a challenge for me when I was secretary to sort of [diversify the force] because you do have a certain system of promotions,” Cabral said during an interview with Boston Public Radio on Thursday. “If you’re not hiring people at the trooper level, you don’t have people of color to promote to supervisory positions.”

Cabral also sympathized with law-abiding troopers who may have been aware of malfeasance, but feared retaliation if they spoke up. She said that much of the culture of the state police is directed by whomever is in charge.

“If you have someone who’s in a position of power and is comporting themselves in a particular way, it does have a trickle down effect all the way down to the rank and file troopers who are patrolling the streets,” Cabral said. “That’s the real challenge for people who care deeply about their jobs and approach their jobs with integrity.”