More questions are being raised about the computer technician who worked on Hillary Clinton’s private email server, this time by the head of the Senate Judiciary Committee.

In a letter sent last week, Iowa Sen. Chuck Grassley, the chair of the Committee, asked FBI director James Comey about Paul Combetta’s role in the ongoing email fiasco.

The Republican questions whether Combetta, a technician with Platte River Networks (PRN), the company that began managing Clinton’s server in 2013, was ever represented by Hillary Clinton’s lawyers, Cheryl Mills and David Kendall.

He also asks Comey why investigators failed to ask Combetta about a conference call he had with the Clinton lawyers on March 31, 2015, the same day that he used a computer program called BleachBit to delete backups of Clinton’s emails, which were under congressional subpoena at the time.

Combetta emerged as a central figure in the Clinton email scandal last month after The New York Times reported that he was granted immunity by the Justice Department in order to cooperate with the investigation.

The FBI’s report of its investigation shows that Combetta lied to investigators during at least one of his three interviews. He misled on the question of whether he knew Clinton’s emails were under a preservation order when he deleted the backups.

He made that deletion on March 31, 2015, just minutes or hours before he took part in a conference call with Mills and Kendall, Clinton’s attorneys.

But, curiously, Combetta refused to discuss that conference call with federal investigators. Acting on the advice of his lawyer during a Feb. 18 interview, he either invoked his Fifth Amendment right against self-incrimination or cited attorney-client privilege. The FBI’s notes make reference to both types of privilege, Grassley says.

The timing of the deletion and Combetta’s refusal to talk about the conference call raises the questions: was Combetta acting on the orders of Clinton’s lawyers? And did he and PRN have a financial incentive to protect Clinton?

As The Daily Caller has reported, an invoice that PRN purportedly sent to Clinton’s accountant last September shows that the company billed $250 per hour for “federal interviews” that Combetta sat for that month. (RELATED: Tech Firm Charges Clinton $250 An Hour For ‘Federal Interviews’)

Combetta told the FBI that nobody ordered him to carry out the BleachBit deletion and that he had an “Oh, shit!” moment when he realized that he was supposed to excise the backups months earlier. During a House Judiciary Committee hearing last week, Comey said that investigators could find no evidence that Combetta was ordered to delete the backups.

But Grassley is not satisfied with Comey’s answers. He wonders if Combetta was also being represented by the Clinton attorneys or if Clinton was paying for any of Combetta’s legal expenses.

“Did the FBI attempt to determine whether the Clintons or their associates paid for Mr. Combetta’s or any other witnesses’ legal bills or whether these witnesses were a party to a joint defense agreement?” Grassley asks in the letter.

“Was Mr. Combetta a party to any joint defense agreement or were his legal fees being paid by the Clintons or their associates?”

Grassley also points out that the FBI’s notes from its most recent interview with Combetta, which was conducted on May 3, do not make reference to the crucial March 31, 2015 conference call.

Combetta was asked in his Feb. 18 interview about what was said in that conference call, but his attorney directed him to not answer the question, citing “protections under the Fifth Amendment.”

“It is odd, however, that after granting him immunity, there appears to be no record that the FBI questioned him about the March 31 conference call and no record of his description of Director Comey September 28, 2016 that call, the only topic which he had previously refused to testify,” the letter reads.

But in a memo released earlier last month, the FBI stated that Combetta refused to answer the questions based upon the assertion of attorney-client privilege.

“In his third interview, did Mr. Combetta describe his memory of the conference call with Secretary Clinton’s attorneys? If so, why is it not reflected in the relevant interview report?”

Combetta invoked his Fifth Amendment rights during a House hearing last month.

A public relations firm working for PRN has declined several requests for comment.

Follow Chuck on Twitter