"As I approached them, two of them ran up to my car," Boston College Police Officer Carl Mascioli told WBTS. "There was a body in the water."
The officer arrived to find the man motionless in the water and, while pulling him onto dry land, Mascioli said he noticed a swastika tattoo on his hand.
"I kind of let the gentlemen know sometimes some deeds have a funny way of turning around," Mascioli said. "Their good deed had a little bit of a twist to it."
The students, who were not identified, told Mascioli they didn't have any regrets about their role in the rescue -- but they said they wanted the man found in the reservoir to know "it was four young Jewish boys that helped save his life."
"A good deed is a good deed and that's part of life," Mascioli said. "We should be helping everybody out."
Authorities said the man is expected to make a full recovery.
The Associated Press contributed to this report.