A Gilbert man is expected to plead guilty to making threatening phone calls to a former federal prosecutor.

James Giannakos Jr. also has been linked to the riots at the US Capitol in January.

Prosecutors say Giannakos Jr. was mad about information released on the leader of the alt-right group Proud Boys.

During a Feb. 3 search of the his home, FBI agents found multiple items, including a US Capitol Police shield, which federal law enforcement said in court documents showed “probable cause” that Giannakos Jr. participated in the mob that overran the Capitol.

The FBI also confiscated a “riot bag” that contained a map of the District of Columbia’s Metro system, eye protection, a bike helmet, a tactical vest with hard plates, baton, flashlight, masks and gloves, according to a search warrant filed in federal court.

Giannakos Jr. is charged with making interstate threats.

This came after the leader of the Proud Boys, Enrique Tarrio, gave the government information used to incarcerate people.

Reports say the former assistant US attorney, who is the victim in this case, “indicated that the information Tarrio provided to authorities led to the prosecution of approximately 13 individuals.”

Federal officials claim that on Jan. 28, Giannakos left a threatening voicemail for the former assistant US attorney, who lives in Miami, because he was angry Tarrio’s name was reported.

FBI agents were able to trace that phone number to Gilbert and eventually to Giannakos. An FBI agent filed an affidavit to get an arrest warrant for him on Feb. 2.

Court documents also show he was previously convicted of assault and battery of a high and aggravated nature and claims he is unemployed.