CHICAGO — Chicago Mayor Rahm Emanuel on Tuesday released a proposed ordinance that creates a new agency to investigate police misconduct to replace the agency that came under fire in the wake of a video of a police shooting of black teenager Laquan McDonald.

But Emanuel, who had hoped to bring the ordinance to the City Council for a vote on Sept. 14, pushed a vote back until Sept. 29 after aldermen said more time was needed to get input from the public.

The ordinance that calls for the replacement of the Independent Police Review Authority with what is called the Civilian Office on Police Accountability also creates a new deputy inspector general position that would have the authority to investigate the police department.

The moves are part of Emanuel’s effort to restore public trust in the police force and his own leadership in the wake of the release of the McDonald video that led to reports that IPRA often took months or even years to investigate officer-involved shootings and nearly always sided with the officers. In a statement, the mayor addressed public skepticism, saying that “The path forward will be about … implementation, culture and building community trust in the system of police accountability.”

Under the ordinance, the new agency would investigate shootings, incidents when officers used their Tasers, allegations of physical and psychological coercion of witnesses by officers, allegations of improper searches, and allegations that officers have denied suspects access to attorneys.

To address concerns stemming from the length of time IPRA over the years took to investigate shootings, the new agency would be required to complete investigations within six months or offer an explanation to the mayor’s office, the police superintendent and others why an investigation has not been completed. Then it must issue similar reports every six months until the investigation is completed.

The ordinance also calls for the creation of a new position of deputy inspector general for public safety who will review and audit the police department and the city’s police board. Emanuel has promised that probes of the department will be independent and under the ordinance the person appointed to the post cannot have ever worked at the police department, police board or IPRA.

Though Emanuel agreed to slow the process down, there is also pressure to act quickly, much of it stemming from concerns voiced by the head of IPRA who has informed the mayor that more and more staffers who know the agency is about to be abolished are quitting, which has made it increasingly difficult to conduct investigations.