A sidekick of Aaron Hernandez is cooperating with authorities in what one former prosecutor called a key development in the murder case against the ex-Patriots star, as new evidence emerged yesterday potentially tying him to the slaying of Odin L. Lloyd.
Court documents obtained yesterday show that Carlos Ortiz — who authorities say was with Hernandez when the Dorchester amateur football player was executed in North Attleboro on June 17 — has flipped on his friend.
Ortiz, who hails from Hernandez’s hometown of Bristol, Conn., talked to state troopers in Connecticut last week and directed cops to a secret crash pad in Franklin leased by Hernandez, court papers show.

“Ortiz did confirm that he was with Aaron Hernandez on the night in question,” state trooper Michael Bates wrote in an affidavit filed in Wrentham District Court. “Ortiz then went on to explain that Hernandez has another address that not many people know about. Ortiz referred to this location as an apartment-style location, commonly referred to as a ‘flop house.’ ”
Former Middlesex District Attorney Gerard T. Leone, now a private attorney not connected to the Hernandez case, said 
Ortiz’s cooperation could be a dagger for prosecutors.
“If it is in fact shown that he was in the car leading up to and during the killing, then that type of witness would be huge,” 
Leone said. “From a defense perspective, it’s obviously damaging. But the prosecution will need as much corroborating evidence as possible.”
Ortiz, a career criminal, was arrested in Connecticut last week on weapons charges in connection with Lloyd’s slaying. If his information checks out, he likely would be offered a deal for his testimony that could include a lesser charge or even immunity from prosecution, Leone added.