BRISTOL, Conn. -- Boston police have been investigating whether former New England Patriots tight end Aaron Hernandez may have been the gunman in a 2012 double slaying in their city, according to a search warrant request released Thursday.

Hernandez, who is jailed awaiting trial on murder charges in a 2013 shooting near his Massachusetts home, was seen on surveillance footage in the same nightclub as the victims on the night of the attack in Boston's South End, authorities have said.

But newly released documents in Connecticut confirm for the first time that police suspect Hernandez could have carried out the shootings.

No charges have been filed in the deaths of Daniel Jorge Correia de Abreu and Safiro Teixeira Furtado, who were killed on July 16, 2012, after someone inside an SUV opened fire on their car. A third person was shot but survived.

A June 28 police affidavit and search warrant application released by Superior Court in Hernandez's hometown of Bristol, Conn., says there is probable cause to believe Hernandez was driving the vehicle used in the shootings and "may have been the shooter."

The affidavit was filed as police sought to search an SUV they say was used in the shootings and subsequently found at Hernandez's uncle's home in Bristol. The SUV had been given to Hernandez by a Rhode Island company in exchange for participating in promotional activities, according to court filings.

Authorities found the SUV while investigating the slaying of Odin Lloyd, a semi-professional football player whose body was found June 17 in an industrial park near Hernandez's North Attleborough, Mass., home. Hernandez has pleaded not guilty to murder in that case.

A lawyer for Hernandez did not immediately respond to a request for comment.

Copyright 2014 by The Associated Press