The Federal Bureau of Investigation (FBI) has arrested a 42-year-old US government contractor accused of leaking classified national defence information to a person who allegedly published sensitive intelligence material online.

The United States Department of Justice identified the suspect as Ian A. Brinksman, of Washington, DC. He was arrested on Friday, October 23, following a search of his residence and charged by criminal complaint with unlawfully transmitting national defence information.

According to the Justice Department, Brinksman previously worked for a US government agency before joining a private contractor providing services to the same agency in 2022.

During the period covered by the allegations, he held a top-secret security clearance that gave him access to Sensitive Compartmented Information (SCI), a category of highly restricted intelligence.

Prosecutors allege that Brinksman repeatedly accessed classified reports beyond the scope of his official duties and passed information to an individual with whom he had a romantic relationship. The individual operated a publication on Substack, an online platform used to distribute newsletters and articles.

The Justice Department said the publication had carried articles containing information allegedly derived from classified government assessments. Investigators claim that at least five articles published in 2026 contained material closely matching classified reports accessed by Brinksman.

According to the criminal complaint, investigators examined records including communications, database access logs, building entry records and emails as part of their inquiry into the alleged disclosures.

Assistant Attorney General for National Security John A. Eisenberg accused Brinksman of obtaining sensitive material outside his authorised responsibilities and sharing it with someone he allegedly knew intended to publish it.

“That is not carelessness. It is a betrayal of his oath and the American people who entrusted him to fulfil his duties honourably,” Eisenberg said.

US Attorney General Todd Blanche said the Justice Department would continue prosecuting individuals accused of unlawfully disclosing classified information that could threaten national security.

FBI Director Kash Patel also described protecting government secrets as a counterintelligence priority, warning that officials and contractors who allegedly misuse positions of trust could face prosecution.

The case is being investigated by the FBI’s Chicago Field Office, with assistance from its Washington Field Office. Prosecutors from the Justice Department’s National Security Division and federal prosecutors are handling the proceedings.

The criminal complaint identifies the alleged recipient of the information as “Individual 1” rather than naming the person in the document. Reuters reported that the evidence described in the filing corresponds to articles published by journalist Aída Chávez through her Capital & Empire newsletter on Substack. The allegations against Brinksman remain to be tested in court.

Brinksman has been charged with unlawfully transmitting national defence information. The charge is an allegation, and he is presumed innocent unless and until proven guilty beyond a reasonable doubt.