Patrick Keogan, 44, of Wilmington, Massachusetts, who is suspected in threatening two mosques, was back in court Friday for a probable cause hearing.
Keogan was arrested after posting threatening images on social media the day after the terrorist attacks in Paris.
He admitted to the FBI that he sent posts to the Facebook pages of the Islamic Society of Boston and the Islamic Center of NE University showing a picture of a burning mosque and the words "Burn your local mosque." And "Hello scumbags" alongside smiley face emoji.
His attorney argued there is a fine line between free speech under the first amendment and threatening.
Authorities say Keogan, who is a convicted felon, unlawfully possessed ammunition.
The prosecutor pointed to a history of threats and violent conduct Keogan has been convicted of and the presence of more than 40 guns and ammunition in his home as evidence this is a dangerous man.
The judge did find probable cause to proceed with the case.