The NYPD detail assigned to de Blasio traveled with him around the country, transporting him while he was campaigning for president in 2019, even though city rules limit the use of official vehicles for political travel to trips in or around New York City.

The probe is the latest investigation to find that de Blasio played fast and loose with ethics rules and comes as he eyes a potential run for governor.

The NYPD spent $319,794 on travel for de Blasio’s security detail outside New York — shelling out for flights, hotels, rental cars, gas, and meals. Neither de Blasio personally nor his campaign have paid the money back. The figure accounts for only travel costs, not overtime and salaries paid to detectives during the campaign trips.

Multiple cops on the detail and an NYPD sprinter van were used to assist de Blasio’s daughter, Chiara, when she moved from a Sunset Park apartment back in with her parents at Gracie Mansion. One detective helped move a futon belonging to the first daughter, according to the report.

The detail also drove Dante de Blasio back and forth to Yale University on several occasions without the mayor or his wife, Chirlane McCray, present, investigators found. And for several months in 2019 and 2020, after Dante had graduated college and moved back to Gracie Mansion, they drove him every day to work in Brooklyn.

Redmond, the head of the detail, refused for months to turn over his city-issued phone, deliberately sought to destroy his NYPD phone after he was told to surrender it and deleted communications from two phones, according to investigators. He also gave testimony in an interview with DOI that was not credible.

DOI Commissioner Margaret Garnett said at a news conference Thursday that the mayor’s office lacks a clear policy on how the detail should be used.

“It frankly is just an invitation to corruption and waste of public resources,” she said.

De Blasio blasted the report Thursday.

“I am literally shocked of the number of inaccuracies in this report,” de Blasio told reporters in a separate press conference.

His spokesperson also bashed the investigation.

“Intelligence and security experts should decide how to keep the mayor and his family safe, not civilian investigators,” Danielle Filson said in a statement.

“This unprofessional report purports to do the NYPD’s job for them, but with none of the relevant expertise — and without even interviewing the official who heads intelligence for the City," she said. "As a result, we are left with an inaccurate report, based on illegitimate assumptions and a naïve view of the complex security challenges facing elected officials today.”

Garnett rejected the criticism.

"I don't think that a mayor who is interested in an independent and effective DOI would be saying that,” she said.

The mayor and his family members frequently receive threats, his office says — with 308 recorded during his tenure, including dozens that specifically referenced his family.

DOI investigators found that the security detail has been used to conduct checks at homes de Blasio owns in Brooklyn — where his family has not lived since 2014. At least one of the homes is used as an investment property with paying tenants.

The detail also ferried around the mayor’s brother — picking him up from the airport, driving him to pick up a Zipcar in New Jersey and driving him to an Alamo rental car location — as well as de Blasio’s guests.

They drove mayoral staffers home or to other locations without de Blasio present on multiple occasions, including one incident where a City Hall staffer and Redmond spent three hours drinking at a Manhattan bar while a detective waited outside.

De Blasio has resisted reimbursing taxpayers for the costs of his detail’s presidential campaign travel. His lawyer appealed a ruling from the Conflicts of Interest Board that he owes the money, arguing that he must not “be forced to risk his life” by foregoing security.

But Garnett said ethics rules require the money to be paid back, noting that other presidential candidates either hired private security or reimbursed taxpayers for the use of their official details.

"When the rules exist, they apply to everyone, including the mayor,” she said.

De Blasio has previously been dinged by the Federal Election Commission for mingling finances during his presidential bid and was found to have improperly sought donations from people with business before his administration.

The mayor argues that the use of detectives to transport his kids is appropriate because the NYPD determined they are entitled to security protection. But Chiara and Dante, as adults, declined to have a security detail — and NYPD cops were instead used with no security rationale as occasional chauffeurs, according to DOI.

“Security is not being provided in any meaningful way,” Garnett said. “It’s not security, it’s essentially a concierge service.”

While de Blasio was not referred for criminal investigation, he could face fines from the city Conflicts of Interest Board.

“I am acting in good faith always. I’ve followed whatever guidance is given me,” de Blasio said at his press briefing.

He called the investigators “unprofessional and unfair and inaccurate” because they did not interview John Miller, deputy commissioner of Intelligence and Counterterrorism for the NYPD, who appeared at the news conference to back the mayor’s defense.

“The mayor of the city of New York, whether it’s this mayor or any other mayor, is a nationally recognized figure, particularly now in a very brittle political environment in this nation. That comes with its own implicit threat,” Miller said.

Amanda Eisenberg contributed to this report.