Traficante and his girlfriend were fishing, said Deputy Chief Kurt Blanchard of the Environmental Police.
After Traficante went into the water, his girlfriend went in but could not locate him.
Leduc, who lives near the pond, was off duty. He drove his Jet Ski to the scene after hearing a report about the missing man, said Denise deMedeiros, who was with Leduc and saw him enter the pond with his diving gear.
"It didn't seem like he was in distress," she told The Newport Daily News.
Divers from Westport, Mass., soon spotted Leduc motionless in the water.
He was pronounced dead at St. Anne's Hospital in Fall River, Mass.
An autopsy will be conducted.
Dozens of firefighters gathered around the shore yesterday while four dive teams searched the pond for Traficante, Blanchard said.
One resident, Joseph Arruda, watched from his van parked near a boat ramp.
Arruda credited Leduc with saving his life in 1982 by tying a tourniquet on his leg to stop the bleeding after a car accident.
"If it wasn't for him, I wouldn't be here today," Arruda said.
