The fiercest critics of Honolulu’s controversial elevated rail project — and even many of its supporters — have been asking the same question for a long time: With its current $9.2 billion pricetag, where has all the money gone?

Now, a legal process has begun that could yield some of those long-sought answers, as well as some unpredictable consequences that at least some members of the public would rather avoid.

The Honolulu Authority for Rapid Transportation, the agency in charge of the project, has now received two federal grand jury subpoenas for information about the way construction of the 20-mile line is being handled.

The city’s beleaguered system, encompassing the concrete guideway and its 21 stations, has faced delays and skyrocketing costs nearly from the start of construction in 2012.

Now it’s at a particularly sensitive juncture, still awaiting final approval from the Federal Transit Administration of its latest “recovery” financial plan. That approval is needed to secure the remaining allotment in the FTA’s full-funding grant of $1.55 billion, which is essential if the project is to push forward to complete the planned East Kapolei-to-Ala-Moana alignment.

The recovery plan was necessary because funds were running short to get the project past Middle Street. The approach to the city center is where some of the most complex construction — and property relocation challenges — will occur, so it’s imperative to get costs under better control.

In the final analysis, more information can reveal where money has gone astray, which could be useful guidance as the project moves toward its latter stages. The less-rosy view would be that the grand jury inquiry could uncover malfeasance or generally cause persistent disruptions to the work — and at this stage, either dose of judicial “medicine” could kill the patient.

Andrew Robbins, HART’s chief executive officer since September 2017, is taking the only rational approach at this stage, and that is to comply with the requests for documents while remaining focused on the agency’s pursuit of financing arrangements for the crucial, final increment: the City Center phase of construction.

But the following developments have made it tough to stay on task, to be sure:

>> In December, the Honolulu Star-Advertiser reported that federal investigators were taking an interest in the project, and on Feb. 14, it became clearer what that entailed. That’s when HART confirmed being served with the first, sweeping subpoena from the U.S. attorney’s office and the FBI.

HART was asked to turn over documents going back nearly to the start: consultant contracts, the roster of contractors and subcontractors, contractor change orders and sup­porting documents, archaeological studies and correspondence with the FTA, according to a statement from HART.

This request, though startling, was downplayed as not terribly disruptive: Officials said it comprised roughly the same document set that HART had provided to the state auditor for his recent report.

>> Days later, a new subpoena came down, this one requesting data about payments made to tenants and property owners who had been relocated to make way for the train.

This request called in 18 files on the payments, documents that had been part of HART’s own internal review, Robbins said. The authority had written to the FTA about the issue a year ago, and in that letter identified problems with 15 of the relocation cases, noting missing documentation errors and insufficiently justified payments.

The sum of it was that these were some of the most expensive relocations, including some in which payments exceeded federal guidelines.

Robbins said he does not know the amount of overpayment, adding that he did not believe any of the agreements involved illegality. We certainly hope that is the case.

All of this is happening in the midst of tense relationships with state lawmakers, many of whom in 2017 agreed to a state financial bailout package only under duress. The recent events have done little to ease their consternation, and with good reason.

If there was any vestigial hope for further budgetary help from the state — which always was a long shot — it’s surely evaporated now. And continuing problems with finances will make the project even more politically radioactive than it already is within Honolulu Hale as well.

The best chances for progress that has eluded HART’s board and executive staff lie in a successful search for a private partner for the final phase. The pursuit of this public-private partnership (P3) plan needs to have top priority.

Those who have endured the knotty traffic tie-ups of the past — including those snarled by rain, accidents and landslides of recent weeks — still want to see a rail system that can provide an efficient alternative route to key destinations. The Star-Advertiser still is counted in that cohort.

For now, as the legal story plays out, all rail backers can do is wait, and hope — and worry, in no small measure.