According to unsealed search warrants, a vehicle wanted in a 2012 double homicide had been rented under Hernandez's name. The July 15, 2012 incident involves a drive-by shooting which left two people dead and a third injured.
A .45 caliber cartidge casing was also found in the car when Hernandez returned it. The casing from that incident matched those found around the body of 27-year-old Odin Lloyd on June 17 in an industrial park. The scene was located a mile from Hernandez's North Attleborough home.
Hernandez's associate Carlos Ortiz has also since come forward and said he was told by another man, identified as Ernest Wallace, that Hernandez was the suspect who pulled the trigger and killed Lloyd. The 27-year-old Boston semi-pro athlete was dating the sister of Hernandez's fiancee, the mother of Hernandez's 8-month-old baby.
Prosecutors say Hernandez, Wallace and Ortiz drove with Lloyd in a rented Nissan Altima to the industrial park where Lloyd was fatally shot.
Ortiz told police that during the drive, Hernandez told Lloyd that Lloyd had been "chilling" with people Hernandez had problems with, the documents say. But Ortiz told police the two men shook hands and the problem seemed smoothed over. However, the Altima soon stopped, and everyone but Ortiz got out to urinate, according to Ortiz's account.
The witness told police he then heard gunshots before Hernandez and Wallace got back into the car without Lloyd and the car sped away.
Records show Hernandez was "argumentative" during his first encounter with police at his home after Lloyd's body was found by a jogger.
"Mr. Hernandez slammed the door and relocked it behind him," the records read. "Mr. Hernandez did not ask officers whose death was being investigated. Mr. Hernandez's demeanor did not indicate any concern for the death of any person."
The 23-year-old ex-NFLer has been charged with orchestrating the execution-style shooting. The gun used in the killing has not been found.
The Patriots released Hernandez following news of his arrest. The 2011 Pro Bowl selection had signed a five-year contract last summer with the Patriots worth $40 million.
The former football star has plead not guilty and is being held without bail.
The Associated Press and ABC News contributed to this report.