The Seattle woman accused of a massive hack of personal and financial data from Capital One Financial Corp. threatened to shoot up an unnamed California social media company, according to court records.

Paige Thompson, 33, was arrested during a raid of her house Monday morning and charged with illegally accessing Capital One’s files. More than 100 million people were affected by the breach, which included names, dates of birth and about 140,000 Social Security numbers, the bank said.

Federal officials also arrested her landlord, Park Quan, after finding more than a dozen guns and explosive materials in his bedroom, prosecutors said. In arguing that Quan should be detained, prosecutors said late Wednesday that Thompson was the “subject of one or more restraining orders and had made express threats to harm others and herself.”

“In fact, in late May 2019, Person 1 threatened to ‘shoot up’ the office of a California social media company,” prosecutors wrote in a filing. A person familiar with the case said that “Person 1” is Thompson.

Thompson’s lawyers didn’t respond to a request for comment. The allegation about the shooting threat was earlier reported by the Associated Press.

Quan, who has at least three prior felony convictions, was charged as a felon in possession of a firearm, according to prosecutors. His attorney didn’t respond to a request for comment.

Thompson, a former Amazon.com Inc. employee, was charged with computer fraud and abuse. A tipster alerted Capital One to the breach on July 17.

The Federal Bureau of Investigation’s probe into Thompson’s social media discovered that she’d posted “about several companies, government entities and education institutions” on a Slack channel, according to court records. In the days since her arrest, the FBI and Amazon have been trying to determine if Thompson’s alleged hacking extended to them or others.

One of those was Michigan State University. Spokeswoman Emily Guerrant said the school was working with the FBI to determine if its computer system was breached. “Other than the old chat logs, we have no evidence to suggest MSU was compromised,” she said.

A spokesman for Milan, Italy-based UniCredit SpA said it was investigating the possibility of a hack and had contacted relevant authorities. In an internal memo issued Thursday and reviewed by Bloomberg News, the bank said, “At this time, there is NO evidence of any customer data having been accessed or compromised.”

Linda Lacewell, New York’s financial services superintendent, said UniCredit, which is regulated in the state, had alerted her office to “the possible loss of consumer data related to the Capital One data breach.” Lacewell said in a statement that her office is examining the matter.

The Ohio Department of Transportation said it was alerted to the issue by media reports and was working with the FBI to determine if the agency was compromised. Ford Motor Company said it too was investigating to determine if it was involved in the breach.

Amazon said Wednesday it had reached out to cloud-computing customers mentioned in online postings by Thompson, but had found no proof she was able to exploit similar flaws at those companies.