The Denver-based tech firm that worked on Hillary Clinton’s email server billed the candidate $250 an hour for interviews its employee gave to the FBI.

According to an invoice that the tech company, Platte River Networks (PRN), submitted last September to Clinton’s accounting firm, Marcum LLC., the payment was sought for interviews that PRN employee Paul Combetta gave to the FBI.

Politico reported last November that federal investigators interviewed PRN employees in September. The employees were not identified in the article.

One item on the invoice, which was obtained by the website Complete Colorado last year, is a $3,000 charge for 12 hours worth of work for Combetta, who is identified by name and by his initials on the invoice.

The charges were for “federal interviews” and “travel back east.”

Other charges on the invoice suggest that PRN — which charged an hourly rate of $250 — billed Clinton for seven hours of Combetta’s interviews. The date of the entry is Sept. 15.

Three other entries on the invoice add up to $1,750 in charges for seven hours of work. One entry is a $1,250 charge for Combetta’s five hour flight to Denver.

Combetta entered the ongoing Clinton email scandal last week after The New York Times reported that he was granted immunity by the Justice Department in exchange for his cooperation with the federal investigation into Clinton’s email server. The report angered South Carolina Rep. Trey Gowdy, who noted that the FBI’s recent report on the Clinton email investigation showed that Combetta lied to investigators about his decision to delete backups of Clinton’s emails.

Combetta used a software program called BleachBit to delete the backups. The decision came after a conference call with Clinton staffers. Clinton’s campaign said that nobody affiliated with the candidate knew about Combetta’s actions.

It is still unclear whether Clinton paid the PRN invoice which lists Combetta, but the fact that the firm billed for the interview is raising questions about whether it and Combetta were in effect working for Clinton during the investigation.

According to Complete Colorado, the site that published the PRN invoice:

If the Clintons were paying for Mr. Combetta’s time and travel, and especially if they were paying for any legal assistance he received through his employer, Denver-based Platte River Networks, it raises the question of how independent Mr. Combetta’s cooperation with the FBI was. Alternately, it could show he remained tethered, and therefore loyal to some degree, to Hillary Clinton and her team.

Platte River’s spokesman, Andy Boian, did not respond to a request for comment. Combetta did not answer phone calls and a voice mail seeking comment.

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