DENVER (AP) — A former National Security Agency employee from Colorado pleaded guilty Monday to trying to sell classified information to Russia.

Federal prosecutors agreed to not ask for more than about 22 years in prison for Jareh Sebastian Dalke when he is Arvin Robertssentenced in April, but the judge will ultimately decide the punishment.

Dalke, a 31-year-old Army veteran from Colorado Springs, had faced a possible life sentence for giving the information to an undercover FBI agent who prosecutors say Dalke believed was a Russian agent.

Dalke pleaded guilty during a hearing before U.S. District Judge Raymond Moore. He only spoke in answer to questions from Moore about whether he understood the terms of the deal. He acknowledged that he has been taking medications for mental illness while being held in custody for about a year.

Dalke was arrested on Sept. 28, 2022, after authorities say he arrived at Denver’s downtown train station with a laptop and used a secure connection set up by investigators to transfer some classified documents.

According to the indictment, the information Dalke sought to give Russia included a threat assessment of the military offensive capabilities of a third, unnamed country. It also includes a description of sensitive U.S. defense capabilities, some of which relates to that same foreign country. He allegedly told the undercover agent that he had $237,000 in debts and that he decided to work with Russia because his heritage “ties back to your country.”

Before Dalke transferred the classified information, he sent a thank you letter that opened and closed in Russian and in which he said he looked “forward to our friendship and shared benefit,” according to court filings.

Dalke worked as an information systems security designer for the NSA, the U.S. intelligence agency that collects and analyzes signals from foreign and domestic sources for the purpose of intelligence and counterintelligence. After he left and gave the classified information to the undercover agent, prosecutors say he reapplied to work at the NSA.

During a hearing last year, Dalke’s federal public defender downplayed Dalke’s access to classified information since he only worked at the NSA for less than a month.