Salvatore Perrone
© Ken Murray/New York Daily NewsSalvatore Perrone
Duffel bag-toting Staten Island man eyed in three slayings of Brooklyn shopkeepers was shifted into protective custody on Rikers Island.

New York -The accused "Son of Sal" serial killer laughed maniacally after his arrest, used his basement as a firing range and fancied himself a patriot in the service of the CIA, law enforcement sources said Friday night.

As triple-murder suspect Salvatore Perrone, 64, was shifted into protective custody on Rikers Island, ahead of a court date set for Monday, new disturbing details emerged.

The suspected psycho's signature duffel bag contained the murder weapon, a sawed-off .22-caliber rifle, police have said. Sources on Friday added that the bag also held a pair of nunchucks, the rifle's sawed-off stock, several knives and clothing.

The knife tied to the murder of the second victim, Bensonhurst merchant Isaac Kadare, 59, was found wrapped in a bloody towel, sources said, adding DNA testing confirmed the 12-inch serrated blade was used in the homicide.

The basement of Perrone's Staten Island home was covered in .22-caliber shells, leading investigators to suspect he was using the space as a crude firing range.
Isaac Kadare, Mohamed Gebeli, Vahidipour Rahmatolla
© Joe Marino/New York Daily NewsFrom left: Isaac Kadare, Mohamed Gebeli, Vahidipour Rahmatolla
A police source said Perrone's motives remained a mystery - he just seemed bonkers. The man dubbed "Son of Sal" by his irritated neighbors told cops he was working for the CIA, a source familiar with the investigation said.

The notion prompted an investigator to ask him, "If you work for the CIA, where's your ID?"

"At the CIA, we don't carry ID," the source said Perrone responded.

Perrone will remain in the jail's North Infirmary wing until his appearance on first- and second-degree murder charges in the killing of Kadare and shopkeepers Mohammed Gebeli, 75, and Rahmatollah Vahidipour, 78. He has admitted to slaying Kadare and Gebeli, police have said.

-With Ben Chapman, Joe Kemp and Stephen Rex Brown