A high-ranking Chicago Police officer and a lieutenant working under that deputy chief were accused Monday of providing a “preferential treatment scheme to reserve and provide free-parking at the United Center” for off-duty cops, their family and friends.

Last year, Inspector General Joe Ferguson unmasked a similar preferential parking scheme at Bulls and Blackhawks games executed by eight supervisors and traffic control aides working at the city’s 911 emergency center.

The new scheme accuses a deputy chief and a lieutenant, neither of whom were identified by name, of engaging in and supervising a similar system of playing parking favorites.

“On numerous occasions, most notably during the Blackhawks’ 2016 Stanley Cup playoffs, the OIG observed uniformed CPD officers allow off-duty law enforcement officers and their friends and family to park on the north and south sides of Monroe Street between Wood Street and Paulina Street,” Ferguson wrote in his latest quarterly report, released Monday.

The inspector general said signs on both sides of the street made clear there was “no parking allowed.” Email reviews and interviews “confirmed” the allegations of favoritism, Ferguson wrote.

“In their interview, both CPD employees offered several meritless defenses as to why the parking scheme existed,” his report says.

“The investigation also established that preferential parking was happening at other event venues throughout the city and that other city departments engaged in preferential parking schemes.”

Ferguson recommended that the Chicago Police Department make it clear to officers that “courtesy parking at events in any city location — whether for themselves, fellow city employees, family and/or friends” was expressly forbidden and would result in disciplinary action.

If there is an “operational need” for off-duty cops and other high-ranking city officials to park on streets surrounding major event venues, special orders and criteria should be drafted to justify the perk and prior approvals should be required, the inspector general said.

CPD responded to Ferguson’s disclosure by reprimanding the chief. The department declined to discipline the lieutenant on grounds that he or she “followed the directions of the deputy chief in good faith.”

The Bureau of Internal Affairs also conducted a review of the officers who benefited from the preferential parking scheme but decided not to discipline them, Ferguson wrote.

A Feb. 7 administrative message to the police states: “Members are reminded that arranging, providing, or utilizing `courtesy’ parking on the public way — whether for themselves or others (such as city employees, family members or friends) is prohibited in the absence of exigent circumstances. Moreover, the use of official authority or resources to extend such ‘courtesies’ my result in disciplinary action.”

In the preferential parking scheme at the 911 center, parking requests from friends and relatives of management-level emergency management employees were sent to city email addresses.

OEMC managers would notify supervisors working outside the United Center of the names and vehicle descriptions of the VIP parkers who should be allowed on Wood. Traffic control aides posted on Warren and Wood and Madison and Wood received similar information.

The inspector general recommended then that the city “take steps to ensure that the parking scheme” was not continuing at other locations and events. It was not known what became of that request.

The Streets and Sanitation employee accused of benefiting from the parking scheme was slapped with a 14-day suspension. All OEMC employees targeted by the IG were hit with suspensions ranging from five days to 30 days.

Emergency Management chose a 30-day suspension over firing the alleged ringleader, as Ferguson recommended, in part, because officials were “not fully convinced the employee set out to deliberately mislead” the inspector general.

To prevent a repeat of the scheme, the department said it planned to provide ethics training for Traffic Management Authority employees with help from the Board of Ethics.