Aaron Hernandez
In a new prison letter, Aaron Hernandez tells a fan that he's "a great dude" and claims that his biggest fear is that daughter Avielle Janelle Hernandez will grow up without knowing him. Screenshot

Just one day after former New England Patriots star Aaron Hernandez was arrested for the alleged murder of Odin Lloyd, sources have revealed that the 23-year-old may be the subject of a second murder investigation.

Boston Police are reportedly investigating Hernandez in connection with a separate double murder, Fox 25 exclusively reports. The alleged crime took place on July 16, 2012, in downtown Boston.

According to Fox 25, a Boston Police blog written on that date stated that officers responded to a crime scene at 2 a.m. that morning. Upon arriving at the scene, police discovered that three people had been shot while sitting in their car at a Boston traffic light.

Two of the victims, identified as Safiro Furtado and Daniel Abreu, would later die from their gunshot wounds. According to the source, Furtado and Abreu, who worked for a cleaning company in Dorchester, Mass., were murdered shortly after leaving a bar in downtown Boston.

Witnesses to the crime stated that Furtado and Abreu were sitting in the front seat of their vehicle when an unidentified party, driving an SUV with Rhode Island license plates, opened fired, Fox 25 reports. While the two men were killed in the shooting, a back seat passenger managed to survive his wounds. Meanwhile, authorities believe that a pair of additional passengers was able to escape from the scene of the double murder.

The source told Fox 25 that police are investigating the possibility that Hernandez was involved in the double murder. However, it is not yet clear what role, if any, he played in the crime.

On Wednesday morning, Hernandez was arrested for the murder of Lloyd, a 27-year-old semi-pro football player. The former Patriots tight end was arraigned on six criminal counts, including murder and illegal firearms charges. He is currently being held without bail.