A man accused of stealing the identity of the former head of the National Security Agency pleaded guilty Friday to fraud and tax charges — but not identity theft.

Carnell King is accused of stealing the identity of Gen. Keith B. Alexander to open new credit cards and file false tax returns.

King pleaded guilty before U.S. District Judge Robert Gettleman to three counts of fraud using an authorized access device and one count of filing a false claim with the IRS.

The 35-year-old Austin man’s admission to the crimes was under a “plea declaration” rather than the standard plea agreement because prosecutors aren’t on board — they had reached no deal with King, according to Joseph Fitzpatrick, a spokesman for U.S. Attorney Zachary Fardon.

Prosecutors told Gettleman they still intend to take King to trial for the remaining, most serious charge: identity theft, which carries a maximum sentence of 15 years.

King faces up to 10 years in prison for each fraud count. Filing a false claim with the IRS carries a maximum penalty of five years.

When the feds raided King’s apartment last year, they said they found evidence that he had stolen a slew of people’s identities, including that of the former NSA chief, Gen. Keith B. Alexander.

John Beal, King’s attorney, previously confirmed Alexander is an alleged victim in the case.

King’s victims also allegedly include a “well-known professional athlete.”

Alexander told a public forum in fall 2014 that when he tried to file his taxes, he learned someone had claimed a $9,000 refund in his name and that the suspect had been caught, according to news reports.

The feds said a search of King’s residence turned up: checks and checking account paperwork in Alexander’s name; a bank letter addressed to Alexander at King’s home; and handwritten notes filled with personal identifiers for people including Alexander. They also found 56 credit cards in the name of “various individuals.”

The complaint against King also alleges that in early 2014, Alexander began receiving mail, emails and phone calls that someone had made several attempts to open credit cards using his personal information. When Alexander tried to file his tax returns that month, the tax software he used told him someone using his name already had filed a tax return — and had been issued a refund.

Alexander later said he received emails from his bank seeking to confirm that he wanted to change his contact information to one of King’s email addresses, as well as an address in Chicago.

The feds said they listened to recorded phone conversations with a bank in which a male identified himself with Alexander’s name. An agent later alleged that voice matched King’s.

Finally, the FBI said someone used two local ATMs, one in Oak Park and another in Cicero, to conduct transactions in Alexander’s name.

In a transcript found in one document, King allegedly told a bank representative while claiming to be Alexander that he was “in the Army” and gets “stationed everywhere.” The bank representative said, “I’d like to thank you for your service, sir,” to which King allegedly replied, “Thanks.”

King is expected back in court on Nov. 4.

Contributing: Jon Seidel