(CNN) - Authorities arrested a Michigan man last week after he allegedly called CNN several times, threatening to kill employees at the network's Atlanta, Georgia, headquarters, according to a federal affidavit.
Brandon Griesemer made 22 calls to CNN on January 9 and January 10 and four calls, which were recorded, contained threats, according to the affidavit, which was unsealed Friday.
Griesemer, whose age was not given, also made disparaging statements about Jewish people, African-Americans and the network in several calls, the affidavit said.
He was charged Friday in US District Court with transmitting interstate communications with the intent to extort and threat to injure. He was released Friday on $10,000 bond.
A family member at Griesemer's home in Novi, Michigan, declined to comment late Monday.
"We take any threats to CNN employees or workplaces, around the world, extremely seriously. This one is no exception. We have been in touch with local and federal law enforcement throughout, and have taken all necessary measures to ensure the safety of our people," CNN said Monday in a statement.
Michigan authorities first crossed paths with Griesemer last fall.
On September 19, a man -- later identified as Griesemer -- called an employee at an Islamic center in Ann Arbor, Michigan, and made derogatory comments about the mosque and Muslims, an FBI agent said in the affidavit.
Ann Arbor police used an online database to identify Griesemer's father as the phone's owner.
Two days later, Ann Arbor police contacted Griesemer's mother at the family's home, where Griesemer lived. She told police her son had called the mosque, the affidavit said. Officers told her they wanted to talk to her son.
In a call to Ann Arbor police that day, Griesemer admitted he called the mosque on September 19 "and that he was angry at the time of the call," the affidavit said.
CNN received the first threatening call around 3 p.m. on January 9. The call was made to a publicly listed phone number at the Atlanta headquarters from the same cell phone number used to call the Islamic center in Ann Arbor on September 19, the affidavit said.
It was the first of three threatening calls that day to CNN from that number, according to the affidavit.
"Fake news. I'm coming to gun you all down," said the caller, who cursed and used an expletive directed at African-Americans, the affidavit said.
"I am on my way right now to gun the f****** CNN cast down .... I am coming to kill you," the caller said a second call to CNN, according to affidavit.
On January 9, an investigator employed by CNN searched law enforcement databases for the phone number and discovered it was registered to Griesemer's father, the affidavit said. The investigator learned a second number was associated with the wireless account.
The investigator called the second phone number and asked to speak to Griesemer's father. The man who picked up identified himself as Brandon, the affidavit said.
The investigator recorded the conversation with Griesemer and compared the audio to the recorded audio of the threatening calls, the affidavit said.
The voices sounded like the same person, the affidavit said.
On January 10, CNN received the fourth call from the same cell phone number used to make the three prior threats, the affidavit said.
The caller again threatened to come to the Atlanta headquarters to "gun every single last one of you," the affidavit said.
The CNN investigator collected data from the cell phone used to make the threats. That phone had accessed a cellular tower in Novi, Michigan, the affidavit said.
Griesemer could face a fine or up to five years in prison if convicted.
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