A Brazilian national living in Marlborough, Massachusetts, pleaded guilty in federal court to trafficking firearms without a license. Guilherme Fernandes-Tavares, 32, entered his plea before U.S. Senior District Court Judge Patti B. Saris, who scheduled sentencing for February 26, 2026.
Fernandes-Tavares was charged by criminal complaint in March 2025 and later indicted by a federal grand jury in July 2025. According to the authorities, between December 2023 and May 2024, he sold 11 firearms and ammunition on ten separate occasions and offered additional firearms for sale.
The weapons included pistols—some privately manufactured without serial numbers—and one pistol with an obliterated serial number. One of the sales involved a large capacity magazine capable of holding 28 rounds of ammunition. Investigators also intercepted a package sent from Florida intended for Fernandes-Tavares that contained another firearm.
The charge carries a maximum sentence of five years in prison, up to three years of supervised release, and a fine as high as $250,000. Sentencing will be determined according to the U.S. Sentencing Guidelines and relevant statutes.
“United States Attorney Leah B. Foley; Thomas Greco, Special Agent in Charge of the Bureau of Alcohol, Tobacco, Firearms & Explosives, Boston Field Division; Michael J. Krol, Special Agent in Charge of Homeland Security Investigations in New England; and Patricia H. Hyde, Field Office Director, Boston, U.S. Immigration and Customs Enforcement’s Enforcement and Removal Operations made the announcement today.” The case is being prosecuted by Assistant U.S. Attorney John J. Reynolds III from the Organized Crime & Gang Unit.
According to officials involved in the investigation, assistance was provided by multiple agencies including the U.S. Postal Inspection Service; Massachusetts State Police; and Westborough Police Department.
