BOSTON (AP) — A man with ties to former New England Patriots tight end Aaron Hernandez visited a Boston courthouse on Thursday after being ordered by a judge to testify before a Massachusetts grand jury.

John Alcorn, of Bristol, Conn., arrived at Suffolk Superior Court shortly after 9 a.m., accompanied by his attorney, Matthew Dyer. Dyer declined to comment as he entered the building with his client.

Alcorn, 21, is related to Thaddeus Singleton III, the deceased husband of Tanya Singleton, a cousin of Aaron Hernandez, said Bristol Police Lt. Kevin Morrell.

Alcorn was also the man nicknamed “Chicago” in a Massachusetts state police report as the possible source of a .38-caliber gun seized from a car after an accident in Springfield, Mass. on June 21, according to Morrell.

Hernandez, a Bristol native, has pleaded not guilty and is being held without bail on a first-degree murder charge in the death of Odin Lloyd, an acquaintance and semipro football player who police said was shot five times in an industrial park near Hernandez’s North Attleborough home in June.

Hernandez’s lawyers have called the case circumstantial and said their client looks forward to clearing his name.

Hernandez also has been linked to the investigation of a 2012 case in which two men were shot near a Boston nightclub. While probing the Lloyd shooting, police found an SUV, sought in the double homicide, at the home where Tanya Singleton lived with her uncle in Bristol. The vehicle had been rented in Hernandez’s name.

Massachusetts authorities have not commented on the nature of the grand jury. A grand jury in another Massachusetts county has already returned indictments related to Lloyd’s death.