The agency overseeing Honolulu rail has been subpoenaed by federal authorities to provide documents related to the transit project’s construction.

The subpoena, which Honolulu Authority for Rapid Transportation officials say they received Monday, requires the agency to provide consultant contracts, lists of contractors, change orders, archaeological studies, and correspondence with the Federal Transit Administration, according to a HART statement issued Thursday.

The move signals a new level of scrutiny — and possible criminal investigation — for a transit project that aims to transform Oahu, yet has endured costly, painful missteps since its inception in the mid-2000s.

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Since December 2014, rail’s budget has nearly doubled from $5.26 billion to what could now be as much as $9.2 billion. The 20-mile, 21-station line was originally planned to start running later this year. Instead, the latest independent oversight firm hired by rail’s federal partners now gives the system a 65 percent chance of running by fall 2026.

The public has never received a comprehensive reckoning of what went wrong.

HART and city officials have repeatedly put the blame on costly state and federal lawsuits that pushed the project into a punishingly expensive construction market. However, recent examinations by the city and state have also pointed to widespread mismanagement and insufficient oversight that helped drive up costs by hundreds of millions of dollars.

A rail spokesman confirmed the subpoena Thursday by abruptly distributing a three-paragraph statement to local media shortly after HART board members wrapped up nearly four hours of committee meetings.

The statement only mentions a “federal subpoena,” without specifying more. HART would not comment any further, according to the spokesman, Bill Brennan.

The subpoena arrives amid a series of withering city and state audits in recent weeks that have slammed HART and the city for shoddy management of the state’s largest-ever public works project. Local project leaders over the years have relied too heavily on outside consultants, failed to properly manage nearly a half-billion dollars worth of change orders, and fed the public rosy estimates that contradicted their own internal warnings of runaway costs.

The city audit plainly states that the project’s approvals were rushed for “political purposes.” Two more state audits, meanwhile, are expected to be released sometime in the coming weeks.

Those audits took place last year. The files that HART must now provide “largely duplicate those recently provided and made available to the state auditor,” the agency statement read.

It’s not clear how many other people or agencies connected to the project have received federal subpoenas. The documents required go back to the project’s beginnings, HART’s statement read.

Former officials pivotal to the project, including former HART Executive Director Dan Grabauskas and former Honolulu Mayor Mufi Hannemann, did not return calls for comment.

In recent weeks, meanwhile, other key figures involved in the project have denied receiving subpoenas.

Cory Lum/Civil Beat

Within city government, the Information Technology Department has previously received a subpoena, city spokesman Andrew Pereira confirmed Thursday.

Mayor Kirk Caldwell was traveling to Japan on Thursday, according to a release issued by his office.

In a statement Thursday, Honolulu’s acting mayor, Roy Amemiya, said “the city encourages and expects HART’s full cooperation with the subpoena for documents related to construction of the city’s rail project.”

“The transit authority needs to continue building greater community trust,” Amemiya said.

HART’s statement on Thursday added that it “pledges its full cooperation in complying with the subpoena and wants to assure our many stakeholders that our staff and contractors will continue to work toward completing the project.”

Meanwhile, the rail agency continues to wait for the FTA to approve its latest version of the project’s recovery plan — a blueprint for how it intends to get progress back on track.

The FTA won’t release rail’s remaining $744 million until that plan gets approved. HART’s current executive director, Andrew Robbins, said the project should be okay as long as it gets that money by July 1.

The rail subpoena landed amid a flurry of activity by federal authorities in Honolulu this week, across separate local corruption scandals. On Tuesday, a new 54-count federal indictment was unsealed against former deputy city prosecutor Katherine Kealoha and her brother, Big Island Dr. Rudolph Puana.

Federal authorities also arrested and charged a high-ranking government official from the Federated States of Micronesia in the latest development in the Hawaii bribery scandal involving local engineer firm Lyon Associates.