The threat, which was made on social media, caused fears of an active shooter on the campus last week, leading to one person being shot and another injured.
The threat against the campus in Annapolis, Md., was made during a time of heightened concern after the murder of a conservative activist on a Utah college campus.
Jinchao Wei provided a Chinese intelligence officer with defense and weapons abilities of U.S. warships, including their vulnerabilities, prosecutors said.
Chinese research ships are studying the seas for science and resources, but the data they gather could also be useful in a conflict with Taiwan or the United States.