When sheriff’s deputies and FBI agents knocked on the door of a married couple’s residence in east Tennessee earlier this year with a news tip in hand, the man who answered the door reportedly told investigators he couldn’t think of anyone who might want to harm his wife, Ann.

One day later, he was charged with orchestrating a murder-for-hire plot on her life.

Nelson Paul Replogle pleaded guilty to federal charges in the Eastern District of Tennessee on Monday after investigators said he paid a hit man $17,853 in Bitcoin to kill his wife on her way to a veterinarian appointment with the family pet and make it look like a road-rage incident or carjacking gone wrong.

The alleged plot was foiled by an unnamed source, who investigators said tipped off the British Broadcasting Corp., or BBC. The BBC then passed the tip on to the FBI.

A defense attorney representing Replogle did not immediately respond to McClatchy News’ request for comment on Tuesday.

Replogle has remained in custody since his arrest on April 21, court documents show. A magistrate judge who signed the detention order said releasing Replogle could put his wife in danger.

“Defendant is alleged to have utilized a virtual currency through Bitcoin to arrange the murder for hire and the Government proffered at the hearing that he was found shredding documents prior to his arrest,” the judge wrote. “Defendant’s release could pose a very real threat to the safety of his wife.”

According to an affidavit filed in support of the charges, Special Agent Clay Anderson with the FBI was contacted on April 20 by the BBC about a “possible threat to life murder for hire” regarding a woman named Ann Replogle who lived in Knoxville, Tennessee.

Knoxville is about 30 miles west of the North Carolina border.

Anderson said he contacted the Knox County Sheriff’s Office, who sent deputies to Ann Replogle’s house to check on her. Anne and Nelson Replogle were both home, though both told deputies and the accompanying FBI agents they didn’t know anything about a threat on Ann’s life.

“Replogle was separated and interviewed alone and advised he did not solicit the murder of his wife and that he could not think of anyone who did,” Anderson said in the affidavit.

Separately, Anderson touched base with the BBC to follow up on the source of the tip. According to the affidavit, the BBC sent him a financial transaction given to them by an unnamed source, which appeared to show payment to an unidentified person for the murder of Ann Replogle. The information provided in the exchange included the date and time of the would-be murder as well as the make, model and color of Ann Replogle’s car.

The payment was made with Bitcoin, the FBI agent said.

Bitcoin is a type of cryptocurrency or digital currency that isn’t operated by a centralized authority such as the government. Bitcoin can be sent and received from unique addresses that function similarly to a bank account number, and it’s typically purchased from a virtual currency exchange.

According to the affidavit, exchanges operating in the U.S. are required to collect identifying information from users.

While Bitcoin transactions don’t contain such identifying information, every transaction is logged on a public ledger known as the blockchain. Anderson said investigators used the blockchain to trace the Bitcoin address that sent the murder-for-hire payment to a virtual currency exchange.

The exchange subsequently provided investigators with the identity of the person behind the transactions — Nelson Replogle, who Anderson said purchased the Bitcoin using money from a savings account to which Ann Replogle didn’t have access.

Prosecutors filed a criminal complaint with Anderson’s affidavit on April 21. Court filings show the government requested Replogle remain in jail pending the case outcome shortly thereafter, which the judge granted on May 4.

Replogle pleaded guilty to one count of murder for hire.

He faces up to 10 years in prison and a $250,000 fine when he’s sentenced Feb. 22, prosecutors said.

Husband paid ‘spellcasters’ to ‘hex’ wife from leaving — then she vanished, CA cops say

Husband accused of killing wife and trying to flee to Mexico takes a plea deal in NC

Ex-wife’s murder-for-hire flops when hitman runs to authorities in Florida, feds say