A 35-year-old Lawrenceville man held in Gwinnett County Jail in a robbery case is now charged with sending threatening letters to a witness, authorities said.

Gonzalo Solis Moreno had been arrested after allegedly fighting with a man and then stealing his car June 15 from outside a Lawrenceville home.

He was charged with robbery, theft by taking and giving a false name or information and is being held without bond on those charges, jail records show.

While in jail, Moreno wrote the witness a postcard and a letter, using other inmates' identity numbers, according to Gwinnett County Police Department reports.

In the postcard, Moreno allegedly threatened the witness and his parents, referred to his cousins and sons looking for the man, and ordered him to give his wife $1,500.

In the letter, Moreno again threatened the witness, said federal agents were watching him and told him to send “a couple thousands dollars” to his wife, a police report said.

Moreno now faces two criminal counts of influencing a witness, jail records show. He is being held without bond on those charges as well.

Jail records show Moreno also is being held for federal immigration authorities.