A man has appeared in court charged in connection with the investigation into the so-called "Punish A Muslim Day" letters.
David Parnham, 35, is accused of a total of 14 offences spanning two years, including one count of soliciting to murder.
He is also charged with two counts of sending a number of letters promoting a "Punish A Muslim Day", capable of encouraging the commission of one or more of a number of offences.
Parnham further faces five counts of sending a substance with the intention of inducing in a person a belief that it is likely to contain a noxious substance, five counts of sending a number of letters conveying a threat and one count of making a bomb hoax.
Parnham, of St Andrew's Close in Lincoln, appeared at Westminster Magistrates' Court on Friday, the Crown Prosecution Service said.
He was remanded in custody to appear at the Old Bailey on June 29.
He was arrested on Tuesday by counter-terrorism police as part of an intelligence operation.
A residential property and office building in Lincoln city centre were searched.