A federal grand jury issued a subpoena Thursday demanding New Britain produce documents related to former Mayor Erin Stewart’s alleged misuse of a city credit card, her challenged tuition reimbursements, a social club membership and the Mayor’s Trophy Charitable Fund.

The subpoena obtained by the U.S. Attorney and the FBI is the first official confirmation that federal authorities have opened a criminal investigation into what a law firm hired by the city has described as a pattern by Stewart of fraudulently obtaining goods and reimbursements worth hundreds of thousands of dollars.

The federal authorities’ initial demand is focused on the rules and records pertaining to Stewart’s use of a so-called P-Card, a credit card issued by the city. An investigation by the Crumbie Law Group found that the great majority of the more than $200,000 charged to the card over nearly a decade were improper.

A representative of the corporation counsel’s office must collect and deliver the documents to a grand jury convened in New Haven on July 28.

Stewart suspended her campaign for governor last month after Crumbie concluded that her personal use of a city credit card was a “repeated and deliberate circumvention of the city’s purchase order system to benefit herself, members of her family, and her political campaigns.”

The subpoena arrived days after the city informed Stewart it wants her to to repay $241,560 to recover tuition reimbursements, severance payments and the legal costs related to investigating how the city says she improperly boosted her income over 12 years running city hall.

Connecticut’s attorney general and commissioner of consumer protection opened a separate investigation last week into Stewart’s handling of charitable assets for the Mayor’s Trophy Charitable Fund, a charity created by her father Tim Stewart, also a former mayor of New Britain.

They have subpoenaed charitable records from Erin Stewart, a bank and a community foundation that helped administer the charity that she continued after taking office a dozen years ago.

The city released the federal subpoena Thursday in response to a public records request made last month by Connecticut Mirror. At the time, none had been received.

Stewart was the front-runner for the Republican nomination of governor until quitting the race on May 14. She since has made no public statements.