A controversial proposal to split control of the Minneapolis Police Department between the mayor and City Council was dealt another blow after the release of a new study found that such an arrangement would be unprecedented among U.S. cities.

The study was one of several assessments of the proposed change released Wednesday by a Charter Commission task force that spent the past several months studying how other cities manage their police departments, among other things.

Proponents of the amendment say that making police answerable to not just the mayor would bring needed transparency and accountability and take a step toward mending relations between law enforcement and the communities they serve.

Police Chief Medaria Arradondo said in response that he had been concerned that such a change “could ultimately do more harm than good for accountability.” He vowed to “continue making myself available to all elected officials and collaborating with the communities we serve and protect.”

The task force, made up of commission members, found that none of the 17 cities studied used a similar model.

“In summary, while we do see some mixing of the forms of government, in the reviewed cities the control of the police department is generally vested in the mayor (mayor-council form of government) or the city manager (council-manager form of government),” the study read. “In those mayor-council forms of government that have police commissions, e.g., San Francisco, Detroit or Milwaukee, the mayor still retains significant authority over the police department because either the mayor appoints the majority of commissioners or because certain authority is reserved to the mayor.”

The sole exception was Oakland, Calif., whose city council has a limited role in approving certain policies from its police commission, the task force found.

A separate analysis cited a lack of existing research into what impact, if any, council control of the police might have on accountability. The task force concluded it was “unlikely that any data or measures currently exist that would be able to support the justifications/purposes of the amendment or test the effectiveness and impacts of the division of authority between the mayor and council proposed in the amendment.”

A final report on the proposal’s feasibility will be adopted at the Charter Commission’s Jan. 2 meeting before being forwarded to the full council for a final vote on Jan. 18.

Still, the findings presented on Wednesday made clear that the commission opposes the amendment, according to City Clerk Casey Carl.

“The Charter Commission’s task force gave a unanimous signal to the full membership that they did not support the proposal,” said Carl.

A movement to cede some of the mayor’s authority over the department to the 13-member council gained steam after the fatal police shooting of Thurman Blevins, an African-American man who was shot in north Minneapolis by two white officers during a foot chase this summer. The matter would be best left to voters, its supporters said.

But a push to get the amendment onto the 2018 ballot suffered a setback earlier this year, when the commission voted to take the rest of the year to study the proposal’s impact and gather public feedback.

Andrea Brown, who runs the Police Conduct Oversight Commission, a civilian body that makes policy recommendations, said that under the proposal, policy decisions would have needlessly been bogged down in bureaucratic red tape.

“There is an immediate need for a policy to be created and implemented, and if the ordinance were to require city council input, we wouldn’t have been able to implement a new policy immediately,” said Brown, a public defender.

The findings were met with relief by Mayor Jacob Frey, who said Thursday that the task force’s position “reads to me like an affirmation of what Chief Arradondo has been saying from the jump.”

“I agree with the intent to achieve greater accountability,” Frey said. “I disagree with the strategy of getting there.”