A lawyer for Aaron Hernandez suggested Tuesday that Russian hackers could have been responsible for accessing the former New England Patriots star's jailhouse phone calls.

"It could be a Russian hacker, with all respect, like WikiLeaks, who was able to backdoor into the system," attorney George Leontire said during a pretrial hearing. "We don't know."

Much of the discussion at Tuesday's hearing in Suffolk County Superior Court centered around Securus Technologies, a Dallas-based company that allowed an unknown person to access Hernandez's jailhouse phone calls as he was awaiting his first murder trial.

Specifically, Hernandez's legal team expressed concern that attorney-client communications may have been improperly accessed.

"We know these phones were hacked. We still don't know who hacked them," Leontire said.

The unauthorized access into a telephone database operated by Securus occurred during the summer of 2014, shortly after Hernandez was transferred to Boston to be closer to his attorneys who were representing him in the Bristol County murder of former semi-pro football player Odin Lloyd. Hernandez has filed a lawsuit against Securus.

The jailhouse phone calls were among several issues discussed Tuesday as lawyers for both sides prepare for Hernandez's upcoming double murder trial.

Hernandez is scheduled to stand trial in February in the 2012 fatal shootings of two men he encountered at a Boston nightclub. Prosecutors say Hernandez gunned down the men after one of them bumped into him. The former tight end has pleaded not guilty in the deaths of Safiro Furtado and Daniel de Abreu.

Hernandez already is serving a life sentence in the 2013 killing of semi-professional football player Odin Lloyd.