CHICAGO (WGN) — John Catanzara, the controversial leader of the largest Chicago police officers union, announced Monday his imminent resignation from the Chicago Police Department.

Addressing the Chicago Police Board during an evidentiary hearing, Catanzara said he would be putting in his retirement papers at CPD headquarters “first thing in the morning” Tuesday.

“It was pretty evident very early on that this cake was already baked,” Catanzara said.

According to union bylaws, the Fraternal Order of Police board could allow for a former member of the department to stay on in a union leadership position.

Catanzara’s announcement came after he faced questions from a city attorney during an evidentiary hearing that would have been used to determine his future with the CPD.

Catanzara, who joined the CPD in 1995, is accused of violating a host of CPD rules with vulgar and incendiary comments that he made on Facebook in the years before he was elected FOP president.

He is also accused of improperly filing complaints against one of his previous supervisors, as well as former CPD Superintendent Eddie Johnson over his involvement in a 2018 anti-violence march on the Dan Ryan Expressway.

“This case is about an officer, John Catanzara, who violated the rules of conduct in efforts to bring attention to himself and, in the process, thumb his nose at superior officers and department directives along the way,” Jim Lydon, an attorney representing CPD Superintendent David Brown, said in his opening statement.

Catanzara, who has faced dozens of misconduct allegations throughout his career, was elected president of the FOP last year, and he’s believed to be the first union leader to hold the job while stripped of his police powers.

The city is seeking to have Catanzara fired from the department. Currently, the CPD pays his salary, though it is reimbursed by the FOP. Union bylaws state that termination from the department would not necessarily preclude Catanzara from continuing as FOP president.

Catanzara has remained a frequent sparring partner with Mayor Lori Lightfoot. Earlier this year, he encouraged officers to shirk a mandate that required all city employees to disclose their vaccination status.

Tim Grace, an FOP attorney, said the city’s approach to Catanzara’s case was “very much a ‘let’s throw everything at the wall and see what sticks’ approach.” Grace characterized Catanzara as a “classic whistleblower” who was seeking to hold CPD bosses accountable.

“The evidence will show that he’s been fighting against hypocrisy and shortcomings in the Chicago Police Department for his 27-year career as a police officer,” Grace added.

The evidentiary hearing is scheduled to last until Wednesday. Another of Catanzara’s attorneys, Jim Thompson, said that Catanzara will deliver his own closing argument.

The typically brash Catanzara pushed back on several questions posed by Lydon, though he did freely acknowledge that he filed the complaint against Johnson, and then another against his former commander after that commander killed the other complaint against Johnson.

Catanzara smirked at several of the questions, sometimes while leaning back in his chair or while resting his head in one of his hands.