BANGOR, Maine — A woman from Burlington, Maine, was arrested Friday in connection to a mail threat addressed to Sen. Susan Collins' Bangor home, stemming from a previous investigation into a letter received by her husband claiming to contain ricin.

Two days after Sen. Collins' husband Thomas Daffron opened the ricin threat letter at home by himself in October 2018, prompting a multi-level police response, a U.S. Postal Service mail sorting facility in Hampden intercepted another suspicious envelope that would later test consistent with starch.

A fingerprint on that envelope led them to a suspect.

Suzanne Muscara, 37, is charged with mailing a threatening communication to a U.S. government official protected under federal law.

RELATED: Letter delivered to Collins' Bangor home claimed to contain ricin

According to the complaint affidavit, Daffron opened and handled a letter purportedly contaminated by ricin on Oct. 15, 2018.

Daffron told investigators he was opening mail while at the house alone and came across an envelope addressed to him bearing a Bangor return address and a name – postmarked in both Tacoma and Olympia, Washington, on Oct. 12, 2018 – with a typed, unsigned letter inside.

The letter claimed it had been "coated in Ricin residue," and said, "Good Luck to you and Susan in the next life" and "your wife has betrayed the people of Maine along with the American people and this will be her downfall."

Hazmat teams responded and determined no ricin was present.

A USPS inspector was subsequently assigned to the case to hand-screen all mail addressed to the Bangor residence.

Two days later, on Oct. 17, a hand-printed envelope addressed to "Susan Collins or current resident" was intercepted at the Hampden USPS sorting facility.

According to the affidavit, the envelope bore Collins' street address and a return street address to a separate residence in Bangor. The letter was leaking a fine white powder, which was tested and found not to contain toxic substances.

Testing at the Maine Health and Environmental Testing Laboratory also revealed its contents: inside, according to the affidavit, was a double-sided, Aetna Medicare Solutions colored flyer, reading "AnthRAX!!! HA HA HA!!!" in blue handwriting on one side, along with a drawn stick-figure with the letter "X" for eyes, tongue sticking out and the word "You" with an arrow pointing at the figure.

The FBI later found the substance to be consistent with starch.

A fingerprint on the outside of the envelope was traced by investigators through the FBI's friction ridge print database and, according to the affidavit, was a match for Muscara's right thumb, recorded during a 2013 arrest in Pennsylvania.

Muscara was visited by FBI agents on April 5 in Burlington, Maine. The affidavit states she admitted to sending an envelope by mail to Collins containing a white powder and said it was not poison. She also reportedly confessed to enclosing a note within the envelope, and recalled using the word "anthrax."

According to the affidavit, she told the agents she thought the letter would be intercepted by law enforcement before it reached Collins and did not believe the note would be taken seriously.

RELATED: Sen. Collins' husband says he's concerned for wife after suspicious letter claims to contain ricin

If convicted, Muscara faces up to 10 years in prison and a $250,000 fine.

She was expected to make an initial court appearance at 2:30 p.m. Friday in Bangor.

Muscara's next court date is Tuesday, April 16 at 3 p.m. Her preliminary and detention hearings will both be held then.

Muscara will continue to be held temporarily until the detention hearing.