A man who escaped from a Mississippi courthouse and is wanted on murder and armed robbery charges is in a standoff with police at a restaurant in Chicago, blocks from the Democratic National Convention. Justin Zimmerman has been sought by the U.S. Marshals Service since his escape in June. Authorities in Mississippi said he was located Tuesday at the restaurant in Chicago. Investigators say he escaped from the circuit court building in Hernando, Mississippi, where he was being held on attempted murder and armed robbery charges. He was also awaiting extradition to Houston, Texas, where he’s been charged with murder.