The police commissioner is rejecting a Department of Investigation report critical of his approach to crimefighting. And the mayor is standing firmly behind him, against the DOI. NY1's Dean Meminger filed the following report.

In typical fashion, Police Commissioner Bill Bratton did not mince words after having a key part of his "Broken Windows" policing strategy strongly criticized.

"That report is basically of no value to the NYPD," Bratton said. "It is deeply flawed and will impact not at all on the practices of the NYPD."

Bratton responded after the NYPD Inspector General, part of the Department of Investigation, found that from 2010 to 2015, the NYPD's strategy of enforcing quality-of-life offenses like public drinking and urination did not reduce the rates of more serious crimes, the opposite of what Bratton has pushed for 25 years.

"This report looks at a specific tactic, the issuance of C summonses, and evaluates Commissioner Bratton's claim last year that an increase in C summonses will lead to a decrease in felony crime. It turns out that is just not so," said Department of Investigation Commissioner Mark Peters.

Mayor de Blasio appointed both commissioners, and he has long pushed for the kind of police oversight the new report provides. But on Thursday, he had his police commissioner's back on the issue of police tactics.

"If a governmental entity puts out a report, we are going to look at it. But I agree with the commissioner. The core findings, we don't see merit in."

Bratton was less diplomatic.

"I think I have a lot more expertise than the IG and, in this case, the Department of Investigation," he said. "The IG exists as an independent entity to monitor the police department. The DOI does not have a role in this matter."

The flaw, according to Bratton, is that the report only looked at six years of policing, and focused on arrests and summonses and not other issues that helped to bring down the crime rate over the last two decades.

The DOI fired back, saying its findings "cannot be quietd by city officials who donot agree with them."

"We have a police IG. Does anyone expect the police IG and police commissioner to always agree?" de Blasio said.

The NYPD has 90 days to officially respond to the report in writing.