Federal law enforcement officials arrested a Massachusetts man on a charge of threatening to bomb a local synagogue and kill its members, the US Attorney’s Office in Massachusetts said Monday.

John Reardon, 59, was charged with one count of using an interstate commerce facility to threaten a person or place with harm via an explosive, according to court documents. In this case, Reardon’s cell phone was the instrument of interstate commerce, according to a criminal complaint.

Reardon has been in custody since his initial arrest by local law enforcement officers on January 25, the US attorney’s office said in a statement.

CNN was unable to reach Reardon’s attorney, Jessica Thrall, for comment.

On the morning of the January 25, Reardon left a threatening voicemail for Congregation Agudas Achim, an Attleboro, Massachusetts, synagogue, federal officials say.

The expletive-laden message threatened to bomb the house of worship and to kill members and their children, according to the US attorney’s office. Reardon then called another local synagogue and a separate Jewish organization, officials said, and he was arrested later that day.

“The allegations here about the series of threats Mr. Reardon made against the Jewish community are deeply disturbing and reflect the increasing torrent of antisemitism across our country and right here in Massachusetts,” Acting US Attorney Joshua S. Levy said. “The numbers do not lie — incidents of antisemitism and Islamophobia are spiking.”

The federal charge against Reardon carries a maximum sentence of 10 years in prison, three years of supervised release and a $250,000 fine, according to officials.

Reardon appeared Monday in US District Court in Boston, where he will return January 31 for a detention hearing, according to court documents.