OAKLAND (CBS SF) – Three men from the East Bay have been arrested and face federal charges in connection with an alleged conspiracy to traffic firearms.

Acting Northern California U.S. Attorney Stephanie Hinds’ office announced Monday that 24-year-old Troy Elias Walker and 40-year-old David Michael Rembert of Concord, along with 27-year-old Daljit Kamal Singh of Hercules, were each charged with conspiracy to deal firearms without a license.

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According to the legal complaint, the defendants were charged following an investigation by the Bureau of Alcohol, Tobacco and Firearms and several other law enforcement agencies into illegal firearms trafficking over Instagram and in-person.

During the investigation, agents conducted multiple undercover buys, which yielded 13 firearms. Agents were also able to purchase 17 Glock conversion switches, which prosecutors said turn the pistols into automatic weapons.

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The legal complaint also alleges that some of the firearms purchased were so-called “ghost guns” which do not have serial numbers.

“Collaboration with our local law enforcement partners is key to disrupting illegal firearms trafficking,” Hinds said. “Working with our partners to combat illicit firearms trafficking is and will remain a high priority in our region.”

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Walker, Rembert and Singh made initial court appearances on Friday and are expected again in federal court on Tuesday. If convicted, the defendants can face up to five years in prison and a maximum fine of $250,000.