After pleading guilty in March to six counts of willful retention and transmission of national defense information under the Espionage Act, former Air National Guard member Jack Teixeira was sentenced today to 15 years in prison for posting “hundreds of pages” of classified military documents on Discord.

Some of the leaked information included sensitive details about troop movements in Ukraine and previously unknown information about US intelligence gathering on other countries like China, Russia, and South Korea.

While stationed at an air base in Cape Cod, Massachusetts, Teixeira was granted a Top-Secret//Sensitive Compartmented Information security clearance necessary for “maintaining and troubleshooting” classified workstations in the intelligence wing. According to the DOJ, he “used a secure workstation at the Otis USANG Base to conduct hundreds of searches for classified documents containing NDI that were unrelated to his duties.”

At first, he shared typed-up versions of the classified documents but later posted actual photographs of the materials — including some labeled “Top Secret” — after other community members didn’t pay enough attention to his posts. The New York Times reported that a trail of digital evidence, including a distinctive pattern on a granite countertop in his childhood home, linked Teixeira to the leaked material.

“Mr. Teixeira is responsible for engaging in one of the most significant leaks of classified documents and information in United States history, which resulted in exceptionally grave and long-lasting damage to the national security of the United States,” Acting U.S. Attorney Joshua S. Levy for the District of Massachusetts said in a statement.