(CNN) -- A gun found during a traffic accident investigation two months ago has been linked to a 2012 double slaying that police are investigating in connection with Aaron Hernandez, law enforcement sources said Tuesday.
After a June 21 four-vehicle crash on Interstate 91 in Springfield, Massachusetts, Jailene Diaz-Ramos, 19, was taken to a hospital. During a search of her vehicle -- which is customary when a car is towed from a crash scene -- Massachusetts State Police found a firearm and several rounds of ammunition, according to the incident report.
The gun's ballistics match the markings on the bullets found after two men were killed outside a Boston bar last year, two law enforcement sources said.
The evidence has been presented to a grand jury hearing details of the double homicide, a law enforcement source said.
Diaz-Ramos was not licensed to carry the weapon and was charged with possession of a firearm without a license, possession of ammunition without a license and improper storage of a firearm, the incident report said.
When asked, the teenager told police the .38-caliber weapon belonged to her boyfriend and that "he was the last one to use the car to visit a football player," according to a law enforcement source with knowledge of the case. It's unclear if she named the football player.
Hernandez, a former New England patriot tight end, is being investigated in connection with the double killing in Boston's South End, law enforcement sources said.
Diaz-Ramos' connection to Hernandez is unclear, but she and her boyfriend are both from Bristol, Connecticut, Hernandez's hometown, police say.
The teenager was released on bail after her initial appearance at Springfield District Court, according to police.
In June, law enforcement sources said they believe Hernandez, 23, rented a silver SUV with Rhode Island registration that was linked to the scene of the double homicide. Police searched for the vehicle for almost a year before locating and impounding, the source said.
Separately, Hernandez is accused with the killing of friend Odin Lloyd, a 27-year-old semipro football player whose body was found in an industrial park less than a mile from Hernandez's home. Hernandez has pleaded not guilty.
CNN's Darius Walker, Lawrence Crook and Eliott C. McLaughlin contributed to this report.