Thaddeus Singleton III of Bristol, Conn., was driving a car registered to his father-in-law, Hernandez's uncle Andres Valderrama, when it went airborne, hit an electrical pole and crashed into the wall of a country club in Farmington, Conn., news reports say.
Passenger Tabitha Perry, 27, was injured in the crash, Farmington police said.
Singleton, who records show has served time in state prisons on various drug-related convictions dating to the mid-1990s, is married to Hernandez's cousin, Tanya Valderrama.
Hernandez, a former New England Patriots tight end, is being held on first-degree murder charges in the slaying of Odin Lloyd. He is also being investigated in connection with a 2012 double homicide in Boston.
According to Bristol police, the home identified as Valderrama's address in Bristol has been searched in the last week, including once Friday in connection with the 2012 case. Carlos Ortiz, one of two other men arrested in connection with the Lloyd homicide, often stayed with Singleton at that house, law enforcement officials told the Courant.