Former Mayor Marty Walsh and Mayor Michelle Wu are both passing on the embattled incumbent Ricardo Arroyo in District 5, but differ on who they want to see replace him on the Boston City Council.

Walsh said he’s backing Jose Ruiz, a retired Boston police officer. The decision puts him at odds with the city’s current mayor, who announced two weeks ago that she was endorsing her former employee, Enrique Pepén.

“Jose Ruiz has been an amazing mentor to so many youngsters in the city as a youth coach and he’s an amazing person,” Walsh told the Herald Thursday. “His whole life has been devoted to being engaged in the community.”

Walsh, who left the Biden administration to run the NHL Players Association, said he has worked with Ruiz over the years when he was a youth coach and Boston police officer.

“He would bring all of that vital experience to the City Council,” Walsh said. “That’s why I’m backing him.”

Walsh’s decision to endorse Ruiz was first reported by the Dorchester Reporter. He is also backing John FitzGerald in District 3, a seat that opened up when longtime Councilor Frank Baker opted not to run for re-election.

Ruiz is viewed as a more conservative option than Arroyo and Pepén, who both describe themselves as progressives. He did not respond to a request for comment. Jean-Claude Sanon, a small business owner, is also running.

The former officer also has the support of the Boston Police Patrolmen’s Association, the city’s largest police union, which said on social media last week that Ruiz, “with decades of public safety experience, is best prepared to serve the residents of District 5 with empathy, integrity and honor.”

Wu said she chose to support Pepén because he would be a “fantastic partner” for her on the City Council, due to their “shared progressive values.” He has also worked for her administration, as the former executive director of the Boston Office of Neighborhood Services.

Arroyo criticized Walsh and Wu’s endorsements in the District 5 race, stating that both chose to support candidates that had previously worked for them.

“Another person has decided to endorse their former employee,” Arroyo told the Herald, referring to Walsh. “I’ve never worked for him. I’ve only worked on behalf of the residents of District 5, and it’s their support that’s important to me.”

Arroyo, a progressive voice on the Council, was backed by Wu in his initial run for the District 5 seat, and again when he was running for Suffolk district attorney. She pulled the latter endorsement, after decades-old sexual misconduct allegations came to light, but later said that she had still voted for him in the preliminary election for DA.

Arroyo has denied the misconduct allegations and charges were never filed.

That particular race landed the incumbent in hot water later, when two federal reports surfaced that revealed U.S. Attorney Rachael Rollins colluded with Arroyo to tip the outcome of the election for Suffolk District Attorney, by leaking information that led to damaging pre-primary news stories about his opponent.

Arroyo has denied any wrongdoing, stating that he had no knowledge Rollins was leaking sensitive information on his behalf, and denied pressuring the state’s top prosecutor to investigate his primary opponent, now-DA Kevin Hayden. Rollins resigned when the two reports were made public in May.

In late June, Arroyo admitted to a state ethics violation, and agreed to pay a $3,000 fine for continuing to represent his brother, Felix G. Arroyo, in a 2018 civil lawsuit involving the city after he became a city councilor. The lawsuit involves sexual assault allegations made against his brother by a former city employee.

City Council President Ed Flynn, who has sparred with Arroyo on the City Council, is also endorsing Ruiz in the District 5 race, according to a Thursday announcement on his Facebook page.

“Jose Ruiz has served our city and the neighborhoods of Boston his entire life,” Flynn wrote. “As a youth sports coach, police officer and community leader, Jose Ruiz understands that city government is about solving problems, improving the quality of life for all residents and providing hope and opportunity to those in need.”

While Flynn’s endorsement didn’t mention Arroyo by name, the District 5 councilor pointed to recent discord between the two, saying that his colleague’s decision to back one of his opponents was “hardly surprising.”

“Ed Flynn was the only ‘no’ vote on my home rule petition ensuring a disabled African American, who served in Vietnam and as a Boston firefighter, received the benefits he deserved,” Arroyo said. “If we couldn’t agree on that then this is hardly surprising.”

Flynn said during that Aug. 9 meeting, that he felt a hearing should be held on the home rule petition before it was voted on, given the Council’s lack of familiarity with the case.

Wu opposes the home rule petition due, in part, to the lack of review. The measure would increase the former firefighter’s pension benefits from 72% to 100%.

“I have advocated and supported veterans my entire life,” Flynn told the Herald, pointing to his time spent in the U.S. Navy. “For Councilor Arroyo to challenge my record is shameful. Arroyo once again is not being honest.”

“He is unable to provide his constituents and the city with positive and ethical leadership,” Flynn added.

Joe Dwinell contributed to this report.