MONTPELIER, Vt. — A former member of the corps of cadets at Norwich University smuggled at least 20 firearms into Canada to trade for drugs that he then sold in Vermont, court documents say.

The U.S. attorney’s office on Monday announced the sentencing of 22-year-old August Nommik, the first time the 2-year-old case was mentioned publicly by prosecutors.

Nommik, of Newport, pleaded guilty in April to charges of possessing a gun in furtherance of a drug crime and using a firearm in relation to a drug trafficking crime. He was sentenced Sept. 5 to more than seven years in prison.

Vermont U.S. Attorney Tristram Coffin wouldn’t say why his office declined to publicize the case before its conclusion. The original indictment, filed on April 1, 2011, was sealed shortly after it was filed.

“For investigative reasons, sometimes we don’t make public the nature of cases until near the end,” Coffin said. “Smuggling firearms is an important type of offense for the government to investigate. We try to be aggressive in doing that and use all the tools at our disposal.”

The court documents said Nommik smuggled the guns — including two AK-47s and one AR-15 assault-style rifles — into Canada one or two at a time from July 2010 to January 2011.

In one case, Nommik had another person acquire a handgun on his behalf. Another handgun was stolen from a Derby home. The 9 mm semi-automatic handgun was recovered about 25 miles away in St-Etienne De Bolton, Quebec, on Aug. 19, 2010, nine days after it was reported stolen in Vermont.

The court documents didn’t indicate whether law enforcement agencies in the United States or Canada had recovered any of the other weapons or whether any had been used in crimes.

U.S. prosecutors said Nommik traded the guns for cocaine and other drugs. Many of the documents filed in U.S. District Court in Burlington remain sealed.

The case was investigated in the U.S. by the Bureau of Alcohol Tobacco, Firearms and Explosives. ATF spokeswoman Debora Seifert in Boston referred questions about the case to authorities in Quebec.

Quebec Provincial Police spokesman Sgt. Claude Denis said he was researching the case and wouldn’t be able to provide information Monday.

Nommik’s attorney, Michael Desautels, didn’t return a call Monday seeking comment.

Nommik was indicted in April 2011 when he left Norwich University, where he was a junior engineering management major.

When Nommik entered Norwich in 2008, he was a member of the corps of cadets, the private military college’s military arm, said Norwich spokeswoman Daphne Larkin. She said privacy rules prevented her from saying if Nommik was a member of the corps when he left school.

The website for the federal Bureau of Prisons said Nommik was incarcerated at the Federal Medical Center Devens in Massachusetts, which offers specialized or long-term medical or mental health care.