Federal investigators with the Department of Justice are asking for more than 30,000 pages of documents from Honolulu Authority for Rapid Transportation as part of a criminal investigation, but HART authorities said they don't know exactly what investigators are looking for.

HART was hit with the grand jury subpoena on Monday. They released a copy of it to the public Friday.

It asks for a number of items including all records of communication with the federal transit administration, any requests for proposals or bids for rail construction, and management contracts.

The subpoena does not say what investigators hope to find.

HART has to produce the documents to the special agent who handed them the subpoena by next month or they will have to appear before the grand jury. HART officials say they will hand over the documents.

"We see the subpoena as a task that we must carry out in terms of delivering documents," said HART executive director, Andrew Robbins. "We have no other information as to how long that will go on, what it's all about other than producing documents."

Robbins said the investigation will not slow down rail construction and progress.

Last month, the state released two of four audit reports on the rail project scrutinizing it's budget and management.

The cost of rail started at around $5 billion is now up to more than $9 billion.

The audit says the project's approvals were used for "political purposes."

The other two audits are expected to come out soon.