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A Michigan man was arrested for sending an email threatening to hunt down and "bleed [out]" an attorney for the whistleblower who set President Donald Trump's impeachment in motion, according to an indictment unsealed Thursday.

Brittan J. Atkinson is alleged to have sent the message to Mark Zaid the day after Trump held up a photo of the Washington lawyer and read some of his tweets at a rally in Louisiana in November.

"All traitors must die miserable deaths," Atkinson's email read in part, the indictment says. "Those that represent traitors shall meet the same fate[.] We will hunt you down and bleed you out like the pigs you are. We have nothing but time, and you are running out of it, Keep looking over your shoulder[.] We know who you are, where you live, and who you associate with[.] We are all strangers in a crowd to you[.]"

Atkinson was ordered temporarily detained after he pleaded not guilty to violating a federal law banning threats communicated across state lines, according to court records. He faces up to five years in prison if he is convicted.

A detention hearing was set for Monday. Atkinson's attorney did not immediately return a request for comment.

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Atkinson's wife told NBC News that his arrest has left her "speechless."

"Was his email tactful? No, it wasn't. Was it kind of disturbing? Yes, it was," Theresa Atkinson said from her home in Beaverton, Michigan. "But him along with several other people in this country are fed up with the bull----. They just want the country to run."

Theresa Atkinson said her husband, a former construction worker, has no job, no guns and no income and is disabled. "He's not in a group of anything except his little clan that plays video games," she said. "He's nothing. He's no one.

"He sometimes has a big mouth, and he does get angry," she added, "but he is not a threat in any way, shape or form, and he has a constitutional right to speak."

The indictment does not identify Zaid by name, but he confirmed to NBC News that he was the recipient of the email. Politico was first to report on the indictment, which was first spotted by Seamus Hughes of the Program on Extremism at George Washington University.

"I hope this indictment sends a message to others that such behavior will not be tolerated by a civil society that is governed by law," Zaid in a statement. "It's not appropriate for anyone to threaten another individual's life, regardless of political views."

"I am very grateful to the FBI and Justice Dept for taking these threats seriously and sending the right message," he added.

Zaid became a subject of sustained attacks from the president and his allies after he came forward as the attorney for the whistleblower who reported concerns about the phone call in July between Trump and Ukrainian President Volodymyr Zelenskiy.

"From the lawyer, a sleazeball," Trump said at the November rally before reading tweets in which Zaid predicted that the president wouldn't finish his first term.

In an interview with NBC News last fall, Zaid said the case was all-consuming.

"This case, from the moment I've been in it, has been nonstop every single day. Obviously, it involves the president of the United States," he said. "We've been warned, 'They're coming after you.'"