"Mr. Blackwell has not provided the necessary leadership to ensure a cohesive operating environment within the department," City Manager Harry Black wrote. "As such, morale is at an unprecedented low level, and the general sentiment throughout the department is that Mr. Blackwell's leadership style has created a work environment of hostility and retaliation."

Blackwell said he "categorically" refutes the allegations and is speaking with his attorney about his next steps.

"In time, people will see the truth, hopefully sooner rather than later," he said. "The powers that be did not value the way I policed."

The city manager cited a litany of concerns with Blackwell's leadership in a five-page letter to the mayor and City Council. Black painted a harsh picture of the police chief's time on the force, accusing him of verbally abusing employees, creating a culture of hostility and having "an unprofessional obsession with publicity and self-promotion."

Report: Police chief threatened, berated staff

Black said he conducted an investigation that revealed serious management issues, some of which were revealed through conversations with the department's brass.

The police chief allegedly threatened and berated individuals in front of their subordinates, superior officers and members of the public, the city manager wrote. Some employees of the police department sought treatment for anxiety and stress as a result of these interactions, he said.

Read the report

Elaborating, Black alleged that after a story in The Cincinnati Enquirer on Blackwell's use of overtime, the chief "illegally threatened" to fire an assistant chief who he believed was responsible for the story and ordered an investigation into a department spokeswoman who he also thought was involved, Black said.

"The incidents described here suggest that Mr. Blackwell expected his subordinates to risk defying state law in order to protect his image and, when they did not, engaged in acts of retaliation against them," the letter said.

The communique also accuses Blackwell of ostracizing his assistant chiefs, to the detriment of communication within the department. Blackwell instead hand-selected officers who were not part of the leadership structure through which to communicate departmental decisions, which Black said was disrespectful of the chain of command.

Blackwell engaged in favoritism by personally doling out overtime duties, Black wrote, adding that Blackwell handed out the assignments without consulting officers' superiors. While it's favoritism at best, Black wrote, an investigation will determine if the actions reach the level of inappropriate use of funds.

Communication concerns

There are also questions about Blackwell's use of vacation time, Black said. While officers have complained they weren't able to reach the former chief because he was out of town, Blackwell has reported using only eight hours of vacation in two years, Black said.

Blackwell also inappropriately requested one of his captains tap contacts for free sporting tickets, and he possessed an "unprofessional obsession with publicity," to the point that he took selfies along the procession route of a slain officer's funeral "in a manner more reflective of a parade," Black said.

The aforementioned investigation of the department showed that 81.5% of police department employees surveyed felt Blackwell had "not communicated a strategic plan, departmental mission or direction," the city manager said. On a scale of 10, with 10 being excellent, respondents rated department morale at 2.29, he wrote.

"Terminating Mr. Blackwell was the first and most important step toward creating a climate in the CPD that will allow it to flourish internally and provide our officers with peace of mind relating to their command structure," Black's letter said.

Black said he tried to help Blackwell address shortcomings within the Cincinnati Police Department -- including via a team-building session with an outside facilitator -- "but he has failed to take my direction and accordingly the problems have persisted."

Blackwell took the oath of office in September 2013, becoming the department's 14th chief. Before that, he served 26 years in the Columbus, Ohio, Division of Police, where he reached the rank of deputy chief.

'Ridiculous assertions'

Blackwell said he hasn't yet seen the report on Black's investigation, and was not given a chance to respond to the "ridiculous assertions" in it.

"I am extremely disappointed, not just for me and my family, but for the city of Cincinnati," he said, adding that he plans to look for a new job in another city.

He said he was grateful for kind words from his supporters.

"The people of this city have loved and supported me and I love them," he said.

CNN's Haimy Assefa and Catherine E. Shoichet contributed to this report.