Court documents indicate that the search of a secret "flop house" leased by former New England Patriots tight end Aaron Hernandez has turned up what police say could be key evidence in the murder case against him.

Police say they learned about the apartment from Carlos Ortiz, a friend of Hernandez's whom prosecutors say was with the ex-player the night he allegedly arranged the shooting of Odin Lloyd.

They then searched the $1,200-a-month apartment in Franklin, Mass., on June 26, according to search warrant records at Wrentham District Court. Among the findings were a white hooded sweatshirt and a cranberry-colored cap in a bedroom, the documents said.

Surveillance video showed Hernandez, 23, wearing a similar sweatshirt the night Lloyd was killed on June 17, the records say.

He was wearing the cap in a picture shown on a local news station taken outside a nightclub June 14, the Friday before the killing, the documents said. Prosecutors say Hernandez was upset at Lloyd for talking to certain people at the nightclub.

"The white sweatshirt could be used ... to assist in linking Hernandez to the scene of the crime," trooper Michael Bates wrote in an affidavit in support of one of the search warrants.

"The baseball hat could help provide the whereabouts of Hernandez on the Friday night before the homicide."

The search also turned up several boxes of ammunition, including .22-, .45- and 7.62-caliber ammunition.

Lloyd's body was found in an industrial park near Hernandez's North Attleborough, Mass., home. Prosecutors say Hernandez, Ortiz and another man drove there with Lloyd that night, though they haven't said who shot Lloyd.

Hernandez's attorneys say the evidence against him is circumstantial and that he's eager to clear his name.

Sources told NBC Connecticut that Massachusetts investigators believe Ortiz and Ernest Wallace went directly to Hernandez's uncle's house in Bristol, Conn., after leaving Hernandez's house in North Attleborough the night Lloyd was murdered.

In another development, Alexander Bradley, an East Hartford, Conn., man who in a civil lawsuit has charged that Hernandez in February shot him in the eye outside a Florida nightclub, was served an interstate subpoena Tuesday to appear before a Massachusetts grand jury investigating the Hernandez murder case, the Hartford Courant reported.

Bradley's lawyer, David Jaroslawicz, wouldn't comment Tuesday about the nature of the alleged dispute between his client and Hernandez. He said the two flew to South Florida together before getting into a dispute at a Miami club.

The attorney said that Bradley, who worked for Stanley Steemer before the shooting, had done some work for Hernandez and that the two also hung out socially a few times and had known each other for several years.

"Whether or not Hernandez shot him deliberately or accidentally only Hernandez can tell us, and right now he's not doing too much talking," Jaroslawicz said in a phone interview.