The investigation into corruption involving top Oahu law-and-order officials continues to widen and now has become even more concerning, touching the city administration for the first time. Given that worrisome development, the public needs to get more answers, and in a more timely fashion, than have been trickling out of Honolulu Hale.

The federal investigation surrounding former Honolulu Police Department Chief Louis Kealoha already has yielded disturbing allegations about public corruption and racketeering for which Kealoha and his wife, former city Deputy Prosecutor Katherine Kealoha, will soon face trial.

The case also has elicited guilty pleas from several former HPD officers, with Honolulu City Prosecutor Keith Kaneshiro receiving a letter from the U.S. Department of Justice indicating he is also a target of the inquiry.

And now the public finds out — rather belatedly — that another “target letter” has gone to City Corporation Counsel Donna Leong, who advised the Honolulu Police Commission on its deal with the former chief. That agreement allowed him to retire with full benefits and a $250,000 severance check.

Mayor Kirk Caldwell, in a press conference Monday, said the federal letter stemmed from Leong’s advisory role in striking that severance deal.

Caldwell added that he had planned the announcement in advance but decided to postpone it.

He did so to give Leong time “not only to retain an attorney but to give that attorney time to examine the facts of the case as she would be asked to speak on her client’s behalf,” said Andrew Pereira, the mayor’s communications director.

For those reasons, and so that the Cabinet could be alerted and Leong’s deputy, Paul Aoki, could take over operations, Leong was not put on administrative leave until Monday, Pereira added.

That seems a needlessly generous allotment of time, with Leong’s leave starting more than a week after she received the Jan. 3 letter. The mayor should have confirmed the letter’s receipt, and started Leong’s leave, much sooner.

Even with presumption of innocence, that’s the right course of action for Leong — and the city prosecutor should do the same. It’s unconscionable that Kaneshiro, an elected official, believes he can carry on his duties while he is plainly under a legal cloud — a particularly direct one, as Katherine Kealoha’s onetime supervisor.

Leong’s attorney, Lynn Panagakos, said in defending her client that “the payment was properly authorized and processed.” That leaves unanswered how the deal was approved without full disclosure of the specific source of the funds.

Cary Okimoto, who was acting chief at HPD at the time the deal was struck, wrote in a letter to department staff Jan. 19, 2017, that he was on the record as opposed to having the severance come from the department budget. The check, dated Jan. 26, listed HPD as the account-holding department.

The deal was negotiated with Kealoha by Leong and Max Sword, former chairman of the Honolulu Police Commission.

Loretta Sheehan, who currently chairs the commission, was the lone “no” vote against the agreement in executive session. She said in a telephone interview Tuesday that the panel approved the settlement but did not know the source of the funds.

Okimoto, who underscored that the department was not involved in the negotiations, was justifiably protective of HPD funds to fulfill its public duty. A fuller disclosure about the settlement is overdue.

The mayor has said he is unaware of any other Cabinet-level officials to have received federal investigation letters and has instructed any of them to alert him promptly if they do. And should that happen, the public must be notified quickly as well.