Two NYPD commanders and a sergeant were arrested Monday in a widening federal corruption probe that U.S. Attorney Preet Bharara said is still ongoing.

Deputy Chief Michael Harrington and Deputy Insp. James Grant were charged with, among other things, accepting free plane trips to Rome, Chicago and Las Vegas from Jona Rechnitz, an Upper West Side resident at the heart of the scandal. Rechnitz, described in the complaint as CW-1, is now a cooperating witness.

In exchange for the gifts, the complaint said, the officers provided police escorts, help with tickets and help with local disputes.

Jeremy Reichberg of Brooklyn, who introduced Rechnitz to Grant, Harrington and other NYPD officials, was arrested on bribery charges. According to the complaint, Reichberg accompanied Rechnitz, Grant and Harrington on the trips. Sgt. David Villanueva was charged with conspiracy.

Police Commissioner Bill Bratton said the scandal does not rise to the level that was investigated by the Knapp Commission of the early 1970s, which exposed systemic corruption up to the commissioner’s office. Nor, he said, does it rise to the level of the Mollen Commission scandal of the early 1990s, which exposed widespread drug-related corruption in the 30th Precinct.

However, in neither of those scandals were there arrests of officials ranking as high as a chief and an inspector. And the lurid accusations, which include hiring a prostitute, threaten a department already reeling from other allegations of corruption, tension over its controversial stop-and-frisk policy, and the police-involved deaths of Akai Gurley in Brooklyn and Eric Garner in Staten Island that fueled the nationwide conversation about race and law enforcement.

The complaint said the Las Vegas trip was taken on a private jet. Besides Rechnitz and Reichberg, it included Grant, an unidentified NYPD detective and two other unidentified individuals.

Rechnitz and Reichberg “arranged for a prostitute to come on the private jet and spend the weekend with the group in Las Vegas. While in Las Vegas, the prostitute stayed in Grant’s room,” stated the complaint, which included that the prostitute “was engaged to accompany the person on the trip and that Grant and the others took advantage of her services.”

Rechnitz met Reichberg and NYPD officials at a dinner for the department’s football team some years ago, the complaint said. Reichberg gave Rechnitz a business card that identified him as an “NYPD liaison,” and told Rechnitz he was a “fix it guy” who could help with traffic and moving violations.

In addition, Villanueva, who supervised the gun licensing bureau, was charged with bribery for expediting pistol licenses while Officer Richard Ochetal, who formerly worked in the gun-licensing division, pleaded guilty to similar charges. And in a superseding indictment, Alex Lichtenstein of Brooklyn pleaded guilty to bribery charges in obtaining pistol licenses.

The investigation continues.