An open-government advocacy group is calling on Minneapolis officials to end an investigation into a leaked draft report that said police urged paramedics to sedate people with the powerful tranquilizer ketamine.

Members of the Committee to Defend the First Amendment gathered Thursday outside City Hall and called for an immediate end to the investigation by an outside firm.

"The city of Minneapolis' intensive investigation into the leak of information to a journalist is completely unnecessary and chills freedom of speech," said Teresa Nelson, legal director for the American Civil Liberties Union of Minnesota and a member of the committee. "Individuals who come across evidence of government malfeasance should not fear retaliation for exposing that wrongdoing."

When the Star Tribune published an article about the draft report, she said, "it resulted in almost immediate permanent change in policy by [the Minneapolis Police Department] to address the issue."

The city's investigation could hurt relationships between reporters and their confidential sources, said Joe Spear, editor of the Mankato Free Press and president of the Minnesota chapter of the Society of Professional Journalists.

"Whistleblowers may be the only way that public finds out about reports and activities the government would rather keep secret," said Spear, who is also a member of the coalition.

City Clerk Casey Carl has said that his office, which is overseeing the investigation, is not seeking to find who leaked the draft report. He said his office is mandated under the Minnesota Data Practices Act to investigate any breach of private data, and the investigation would determine if any breach had occurred.

Jane Kirtley, a University of Minnesota professor of media ethics and a member of the coalition, said the city should already know if there had been a breach of private data because they own the report.

The city hired the St. Paul workplace investigative firm NeuVest to conduct a "neutral workplace investigation," according to the contract. The city agreed to pay the firm $275 per hour. All of the company's work for the city can't exceed $100,000.

The draft report said officers repeatedly requested over the past three years that Hennepin Healthcare emergency responders sedate people using ketamine, at times over the protests of those being drugged, and in some cases when no apparent crime was committed. The draft report was prepared by the city's Office of Police Conduct Review and was circulated within and outside City Hall before it was obtained by the Star Tribune. The final report is now available to the public.

The news coverage sparked a public outcry that led Hennepin Healthcare to halt any study of ketamine use on patients without their consent. The city also hired former Acting U.S. Attorney General Sally Yates to investigate whether its police officers improperly influenced paramedics' decisions to use the drug.

After the news conference, members of the group walked into City Hall and delivered a petition signed by nearly 300 journalists and individuals calling for the city to end the investigation.

Star Tribune journalist Janet Moore, president of the Minnesota Newspaper and Communications Guild, serves on the board of the group, and several dozen Star Tribune reporters and editors signed the petition.