A woman accused of buying bomb-making supplies and plotting domestic terrorism attacks exchanged letters with the man convicted in the South Carolina church shooting and visited Columbine High School, federal authorities said.

Prosecutors described how Elizabeth Lecron had a fascination with perpetrators of mass killings and aspired to follow in their footsteps in court documents filed Monday, when she was charged with transporting explosives and explosive material with the purpose of harming others.

Officials with the FBI and Department of Justice said Lecron, 23, bought hundreds of screws and black powder last weekend.

She appeared in federal court Monday and waived a preliminary hearing. A message seeking comment was left with the federal public defender's office, which will represent Lecron.

Lecron talked with undercover agents and informants about carrying out a mass killing at a Toledo bar and later switched to talking about attacking a livestock farm and a factory where she worked, according to an affidavit.

Authorities have been investigating Lecron and a man she was living with in Toledo since June and say they both talked about carrying out violent attacks. None of those plans were carried out, and the man has not been publicly identified or charged.

A search of their home in August turned up AK-47, a shotgun, multiple handguns and large amounts of ammunition, court documents said.

Lecron began sending letters in July to Dylann Roof, a white supremacist sentenced to death in the killings of nine black worshippers in a racist attack in Charleston, South Carolina, according to the documents. She also sent him a book on Nazis that he had requested.

"You have a lot of people who care for you beyond those walls," she wrote.

In mid-August, Lecron walked onto the grounds of Columbine High School, where a security guard questioned her because he thought she was acting suspiciously, according to the filings. In 1999, two students killed 12 classmates and a teacher at the Colorado school.

Lecron told the guard that she wanted to see the memorial there and later posted photos of the trip.

Undercover agents approached her a week ago, the filings said, and told her they wanted to blow up a pipeline but needed someone to buy the supplies.

"Absolutely," she responded, according to an investigator. "I can't wait to see it on the news."

She met on Saturday with an informant, who gave her money, and she bought the supplies at stores in the Toledo area, the documents said.